Shirt Pocket

Fraternal Twins Monday, October 23, 2017

(I really wanted to embed the teaser trailer for Peter Greenaway's A Zed and Two Noughts above, but alas it's a tad NSFW. Really great movie, though.)

Content warning: some strong language is used in this post. Not without reason.

So, here's something that you might not expect me to say:

Because of the way APFS "file clones" work, no program operating at the file level, including SuperDuper!, can make an exact physical copy of every possible APFS volume.

That's right. There are cases where we can't make an exact copy of your APFS volume. And Time Machine can't either. Nothing can.

That doesn't mean the copy is bad! It just means it might not be as space efficient as the original.

Doomed! Doomed! (Well, maybe not so doomed.)

Remember back in this post where I talked about the demo where Craig showed how fast it was to copy a gigantic amount of data?

I explained back then it was because the files aren't being copied. Rather, APFS creates new directory entries for the files, but references the same data blocks. So nothing is copied, which is fast. This is documented in Apple's APFS Guide.

From the user's perspective, these are different files. They're not like hard linked files, where changing one copy changes the others (not that most users know what hard links are). As far as users are concerned, they're totally separate, even if, at the file system level, they share the same data.

In APFS, if one of the cloned files is changed, even by a single byte, that changed data 'splits off' from the rest, and the files are now physically, and not just logically, separate—some of the data blocks now have two copies: the original ones, and the modified ones.

This process continues as the files diverge further.

The amount of logical drive space taken by the copies is twice the original, of course. However, the amount of actual space taken is, effectively zero...until the files are changed. At which point the space taken is the original plus the number of modified blocks.

This is all handled for you by APFS. You don't really have to think about it.

Quantum Theory?

Until you do have to think about it.

Consider this case: you have a 1TB APFS drive, and three 333GB files, named A, B, and C. So the drive is nearly full.

You then create a folder, and copy the three files into that folder with Finder. Of course, you'd expect the copy to fail and the drive to fill...but it doesn't.

In fact, if you look at the volume's size with Get Info, you may be surprised to see it has the same amount of data on it as was there before you made the copies. But, if you look at Finder's size for the folder, you'll see you now have 2TB of data on a 1TB drive. It's like magic!

At least until you change one of the files.

But now, select those files and folders with Finder and try to copy them to another 1TB drive. What happens?

The drive fills.

A Shitty Analogy

You can't copy it to the same size drive! But why?

The reason is there's no (public) way to find out that two files are actually sharing the same data (they might even only be sharing some of the same data, as I explain above). So, when copied, the "clone" relationship is broken, as is the ten-pounds-of-shit-in-a-five-pound-bag magic. You now have a full ten pounds. It doesn't you end up covered in shit.

But What If You...

Yes, we know:

  • What if you kept track of checksums of every file on the drive, and then made "clones" for each file based on whether the files had the same data?

    Leaving aside how ungodly slow that would be (think about trying to match ten million files to each other via checksums every time you copied), remember that cloning operates at a block level, where some blocks may be shared and some may not be. At a file level, it just won't work.

  • How about using hard links?

    That won't work either: clones and hard links are not semantically equivalent at all, since changing one of the hard linked files would change all of them, by definition.

  • Just ask the file system!

    While there are APIs to create clones, there's nothing there to find out whether two files are clones... and also, the shared data is at the block level, so still, no.

  • Time Machine does it!

    Well, not really. Time Machine does seem to be able to determine if two files are clones (which I assume it's doing with private APIs, because I can't find any documented APIs to determine if two files are clones). When it backs up cloned files, it uses hard links to represent them (since HFS+ doesn't support clones, and Time Machine can only back up to HFS+ volumes), and when it restores, it checks to see if those files are clones (which it tracks in a special database), and restores them as clones to APFS...unless they're restored to an HFS+ volume, where all bets are off.

    But even in the best case, restoring to APFS, when files get 'separated' when they're changed, again, only the part of the file that was changed is separate. The other blocks are still shared. So even though they've jumped through hoops to maintain the clone relationship, there are lots of cases where Time Machine's own copies will increase in size too, and it happens more and more as the files diverge further.

  • You guys are so smart, you figure it out! Why are you asking me?

    Geez, don't get so defensive!

We're All in this Together

So, as you can see, given the low-level behavior, there's really no solution, even when you're Apple.

What does this mean for you? It means you can get in cases where data that fits on a source drive won't fit on a destination, even when the drives are exactly the same size.

To avoid problems, you need enough space to store the full logical size of the data (that is, with all the "clones" separated) when you copy, unless you're copying the entire container at a sector level.

We Good?

Again, this doesn't mean your backup isn't good! It is! It has all your data!

What it does mean is that the data isn't stored as efficiently on the backup. So, it might not fit on your drive when you back it up. And it also might not fit when you restore, if the backup ends up larger than the capacity of the source.

That's easy to check, and the solution is also pretty easy: have plenty of free space on your drives, folks. It's always been good advice, and given all this hidden behavior that happens with cloned files, it's even more important with APFS.

OK, back to the code mines...

Automatic Transmission Sunday, October 22, 2017

Good news: we've set things up on our update server so that the Beta version will now automatically tell you when there's a new beta ready, using our regular update mechanism.

Here's how it works:

  • You "opt-in" to the Beta by installing one of the beta releases from the blog.
  • The update server knows what versions are Beta versions. When you check for updates, and if you're running a Beta, it returns the current Beta, rather than the current production release.
  • At the end of the Beta, we set the final "Beta Update" to the production release as shipped. Everyone with the Beta automatically updates to the production version, and future updates are normal, production updates.
  • If you want to participate in a future Beta, you can do so by downloading and installing a Beta version, and the process repeats.

Hopefully this will make it easier for everyone to keep up with the current Beta releases.

Don't forget, though: if you're running schedules, you won't notice the updates unless you launch SuperDuper! manually... so, if you want to be sure, check for updates manually.

Thanks to all the testers—we really do appreciate your help.

Forward Into the Past! Tuesday, October 17, 2017

Executive Summary

Beta 5 is linked at the bottom of the post: we now copy Recovery volumes from both HFS+ and APFS sources to APFS, and "stash" recovery on HFS+ destinations for restoration to APFS if needed.

Details, Details!

Before the advent of APFS, volumes were rigid elements created by physically partitioning a drive, logically erecting barriers between fixed areas of storage. While in later versions of macOS those barriers could sometimes be moved by the command-line diskutil, that functionality was not exposed in the GUI Disk Utility until relatively recently, and was prone to failure.

Even then, adding, resizing and removing partitions was more convenient and accessible...but relatively fragile. Reliable, extensive partitioning (with a friendly interface) was only available in 3rd party tools like iPartition, because it was able to physically relocate data blocks, change partition schemes, etc. The inherent rigidity of the layout of HFS+, even after the introduction of the intermediate-layer CoreStorage setup, got in the way of reliable volume creation and resizing, making the process risky.

Casiotone Nation

The design of APFS changes and improves all of that. Volumes inside an APFS container aren’t defined by rigid barriers, and their storage doesn’t have to be contiguous. All of the volumes in a given APFS container are extremely flexible and share a common free storage pool managed by the container itself. Creating and deleting partitions is a simple and safe operation. There's no need to create images to try to maximize storage efficiency on a drive, or to store three backups on a given drive: you just add new partitions, and they do what you'd expect. Failure is quite rare and for typically obvious reasons.

The Past is Prologue

When Apple got rid of CDs and switched to Recovery it was, in many ways, a step back. Reliable, immediately accessible, archivable media was replaced by a hidden volume on a drive that could fail. Even though Internet Recovery, an EFI-based failsafe, provided a backstop, it took a long time (and required internet access) when things went really wrong.

Save for bootable encrypted volumes, though, the Recovery volume was a nice thing to have on a backup volume, but not a necessary one. While it wasn’t terribly challenging to copy a Recovery volume, creating the partition for it, given diskutil’s capabilities, was risky. And its contents were also undocumented, even if relatively consistent from release to release.

Given Apple could recreate the Recovery volume during a macOS reinstall (a time consuming but easy operation that put a fresh OS under existing applications and data), and the fact that it wasn't needed for startup or restore, we decided to take a more conservative, safer approach and not copy Recovery.

Not because we couldn’t. But because we didn’t think we should, given the risks involved.

#It Gets Better

The introduction of APFS allowed us to revisit that decision. Because its more flexible volume creation is low-impact, the risks inherent in adding and managing the Recovery volume itself are minimal. Recovery now has its own special, documented “Role” within the APFS container, and its contents follow the pattern established for Preboot. Even encryption is done differently: it's properly managed in Preboot, which can be created and updated by a documented system tool, provided by Apple, further ensuring proper operation and compatibility as Apple makes changes and modifies requirements.

After carefully evaluating the new support and determining there were minimal risks, we decided that we could safely copy and manage Recovery for APFS containers, whether copied from APFS or HFS+ sources. And so we do.

That means we still don't create a Recovery volume on an HFS+ volume for the reasons above...but we can copy from an HFS+ volume to an APFS volume and properly copy its recovery to APFS (since that's as safe as APFS to APFS).

If you're copying HFS+ or APFS to an HFS+ device, we still work when restoring to APFS: we automatically create a Recovery “stash” on an HFS+ volume, and can restore it to APFS when necessary.

Your Well-Earned Reward

While the details above are a bit complicated, the best part is that, as with most other aspects of SuperDuper!, there’s nothing you need to do. The details are handled for you. It just works.

In the end, that’s our goal, and our slogan: Heroic System Recovery for Mere Mortals. We hope you agree.

SuperDuper! 3.0 B5.1


The above is the 2nd post of Beta 5 (I called it Beta 5.1 but the version is the same). The first Beta 5 had a bug in it that caused temporary folder cleanup to fail.

This got through regression because we had tested against a number of bootable volume cases without checking the startup volume on the High Sierra test system itself (as opposed to the thumdrives, etc, that we've got for the various disk cases we handle). We tend not to run that every time because the variations (Erase, Smart Update, etc) take much longer with a huge drive. Alas, the startup volume is a different case...and we missed it.

Needless to say, that case is now checked even though it's slow (vs only during "dogfood" daily-build backup runs).

Ah, public betas This kind of stuff is OK when it's all internal. Sorry about that!

So Many Rabbit Holes, So Little Time Friday, October 13, 2017

The past week's been spent delving into some pretty obscure problems. Special thanks, right at the top, to Jan, who spent a lot of time running special code that fixed some of this stuff. Owe you a beer, Jan.

Also, Beta 4 is linked at the bottom of this post, so if you want to just go there and not read how we got there, well, you won't hurt my feelings. Much. >sniff<

Heading to Entebbe

We had a report from a user that blessing Thunderbolt wasn't working. The symptoms were exactly like the FireWire problem previously reported (see below), which really didn't make sense, given it'd act like a regular SATA device, so it was back to reading a bunch of bless code to try to figure out what was going on.

I think I've figured this one out and, unfortunately, it looks like a bug in bless, at least in one case: RAID volumes.

You may remember that there are special volumes in an APFS container that are used for various purposes. One, Preboot, is responsible for booting tasks. When you bless a regular APFS volume, you're also configuring the Preboot volume in the container to support boot.

Now, one Preboot volume supports all the potentially bootable volumes within a given APFS container (there can be any number of them).

bless, when looking for the Preboot volume, sometimes can't find it, even when it's there. When this situation occurs, if you look at the 'verbose' bless info, you'll see, just before it fails (this is an example from a real user):

Returning booter information dictionary:
<CFBasicHash 0x7f94e2d2e5b0 [0x7fffaa32d5b0]>{type = mutable dict, count = 3, entries =>
    0 : <CFString 0x106669ad0 [0x7fffaa32d5b0]>{contents = "System Partitions"} = (
    1 : <CFString 0x10666a2b0 [0x7fffaa32d5b0]>{contents = "Data Partitions"} = (
    2 : <CFString 0x10666a2d0 [0x7fffaa32d5b0]>{contents = "Auxiliary Partitions"} = (

In this case, it's not seeing any preboot volume at all. But when we look at the output of diskutil, we can clearly see it's there, and has the right role:

+-- Container disk5 40B6CB66-CB84-4913-9D81-E99117C5118C
APFS Container Reference:    disk5
Capacity Ceiling (Size):      750079967232 B (750.1 GB)
Capacity In Use By Volumes:  720822272 B (720.8 MB) (0.1% used)
Capacity Available:          749359144960 B (749.4 GB) (99.9% free)
+-< Physical Store disk4 0A426235-14D4-4F80-A334-DBA686914922
|  ---------------------------------------------------------
|  APFS Physical Store Disk:  disk4
|  Size:                      750079967232 B (750.1 GB)
+-> Volume disk5s1 EDEBF4F8-D55E-41A4-9B91-4C8284696EDA
|  ---------------------------------------------------
|  APFS Volume Disk (Role):  disk5s1 (No specific role)
|  Name:                      Backup Disk (Case-insensitive)
|  Mount Point:              /Volumes/Backup Disk
|  Capacity Consumed:        933888 B (933.9 KB)
|  Encrypted:                No
+-> Volume disk5s2 F8301391-7F37-4827-8189-AF830BA3D59A
|  ---------------------------------------------------
|  APFS Volume Disk (Role):  disk5s2 (Preboot)
|  Name:                      Preboot (Case-insensitive)
|  Mount Point:              Not Mounted
|  Capacity Consumed:        18489344 B (18.5 MB)
|  Encrypted:                No
+-> Volume disk5s3 A75B0F60-9626-4F96-9D94-5AD97155838F
|  ---------------------------------------------------
|  APFS Volume Disk (Role):  disk5s3 (Recovery)
|  Name:                      Recovery (Case-insensitive)
|  Mount Point:              Not Mounted
|  Capacity Consumed:        517365760 B (517.4 MB)
|  Encrypted:                No
+-> Volume disk5s4 5B344BEC-B85B-4373-97D3-081CEA467854
    APFS Volume Disk (Role):  disk5s4 (VM)
    Name:                      VM (Case-insensitive)
    Mount Point:              Not Mounted
    Capacity Consumed:        20480 B (20.5 KB)
    Encrypted:                No

The code that's having problems is in BLCreateBooterInformationDictionary.c in Apple's Open Source bless project. After some additional investigation, it looks like, in this case, if the APFS container is on an Apple RAID, bless can't find the Preboot volume and doesn't properly set up the container.

I've got one user's specific drive on order so I can test in his exact configuration here.

Of course, this doesn't explain every case we've seen, but it at least we think we understand what causes this one.

Re-Fire the Main Course

I dug out a FireWire drive here and created an adapter centipede (USB-C to Thunderbolt, Thunderbolt to FireWire, FireWire to drive) and... I was able to successfully bless and boot from a FireWire drive hosting an APFS volume.

So, while there are some FireWire configurations that bless fails on, it's not a blanket failure. It doesn't look like it's only FireWire RAID drives (some weren't), either. So, we're still investigating.

At this point, I'd generally encourage you to use USB-3/USB-C/Thunderbolt drives for any Macs that support those standards. They're all faster than FW800, have a future (as much as any technology has a future), and work fine.

Connection Required?

We were getting weird intermittent errors on some user systems that, when correlated (an exhausting process, since you have to try to figure out the common elements between a bunch of totally random cases), made no sense: the situations where the copies would fail corresponded to a lack of internet access (whether due to proxies, down connections, down DNS, etc).

What's especially strange about that is that...apart from the version check (and resulting software update, if accepted), we don't access the network. And this was happening to these users at the end of the copy, during the bless action.

Long story short (and thanks to Chuck for running a bunch of tests for me), we use xpath to parse the XML returned by the -plist parameters to various tools (such as diskutil). And that XML has a DTD at the start of it that references - and xpath would try to fetch that DTD, fail, and return a blank result.

Surprisingly simple fix: delete that line from the XML. No more network access, proper result return, everything's happy.

Bold and Robust

Due to an extremely high level of coffee consumption, this new beta fixes those and a bunch of other things. So, enough reading about the details and time to get to downloading.

Thanks, again, for helping out during this process. It's great to see it's working well for almost everyone, and satisfying to be able to resolve problems for those reporting them. Have at the new release, and let us know what you find!

SuperDuper! 3.0 B4

It’s Awfully Quiet Out There Saturday, October 07, 2017

Maybe This Was a Good Week to Stop Sniffing Glue!

Support has returned to a normal post-major-OS-release level, mostly (there's still a lot), so I've got a little time to talk about one of the reported problems that was, I think, of general interest. Generally nerdy interest, that is. But it gives you a little insight into what's happening behind the scenes as we make progress towards GA release.

My APFS Backup Drive Isn't Showing Up in the Boot Menu!

While rare, this problem also occurs with HFS+, and is usually due to a drive that isn't responding correctly at boot time. Working around the issue typically involves attaching the drive after you reach the Option+boot menu: that way, the system and drive get a little more time to talk, and all works out.

But, with APFS, we were seeing a number of users indicating that their drive wasn't ever showing up in the Option+Boot menu, even though the drive was in the Startup Disk Preference Pane, and the usual workarounds didn't work.

On top of that, if the user actually booted up from the drive (from Recovery, the Startup Disk Preference Pane, or whatever), the drive would show up in Option+Boot, even after an Erase-then-copy backup...and even after deleting the various special APFS Preboot, Recovery and VM partitions.

Wait, What? C'mon.

I know! But it's true! And so it took a while to get it to happen in-house. But now that I've figured it makes sense.

Doveryai no Proveryai

Additional investigation showed that you didn't actually have to start up from the drive. You merely had to select it in the Startup Disk Preference Pane. You could then switch back to your original drive without booting, and the drive would now always show up in Option+boot.

Given that, my initial thought (after WTF?) was that there was a new security enhancement at play. Perhaps, with the new "3rd-party applications can't set the startup drive" behavior in mind, Apple had taken another step, forcing users to select a drive as a startup drive using the Startup Disk Preference Pane at least once before it would work from Option+boot.

That sort of made sense, except the drive remained bootable across systems, and so there was no actual protection. So that wasn't it.

Schizoid Embolism?

As I mentioned above, once I had a drive that "worked", it would always work, whether Smart Updated or Erase-then-copied. I could even erase the volume with Disk Utility (which makes sense, since that's what SuperDuper! is doing, after all), and it would continue to show up in Option+boot (once a backup was made, of course).

Every one of these tests would take quite a while. Even with a minimal macOS High Sierra install, a test copy from scratch takes about 15 minutes, so each cycle was pretty costly in terms of time.

But, over time, I found that if I turned on all devices in Disk Utility, and erased the drive rather than the volume, the bad behavior returned. So, clearly, this was an outside-the-volume issue, but it followed the disk regardless of system. And that could only mean one thing.


Don't Touch Me There

If you're not building a Hackintosh, you never have to deal with EFI. And while it's made the news lately due to some security issues with older Mac versions, it's not something you ever really hear about.

Basically, EFI stands for Extensible Firmware Interface (currently it's actually UEFI, but most people still say EFI). As that name implies, it's sort of an operating system inside the BIOS that can do stuff like trusted boot, GUID/GPT partitioning, etc.

So, a device can supply programs that run in that environment when attached. And that stuff is stored in a hidden EFI partition on the drive.

For security reasons, normal applications can't touch EFI.

Openly #Blessed

Given that discovery, the next step was verifying that the Startup Disk Preference Pane was using bless to do its thing (it was), and then looking at all the files bless was reading and writing.

Sure enough, one of the files being read (although not written) was /usr/standalone/i386/apfs.efi, and its presence on the drive was not enough.

Time to hit the Open Source repository. (Which is super useful; thanks, Apple, for releasing this stuff, even if it's unbuildable and references private frameworks.)

Analyzing the code there showed that, indeed, bless was embedding an APFS driver into EFI using a private, privileged API that we couldn't (and wouldn't want to) use. Interestingly, it was being done during the processing of --setBoot, the option that actually makes a drive the current startup volume. So there we go!

Don't Do Me Like That (RIP TP)

Except SuperDuper! can't use --setBoot, because it gives an error: only Apple apps can use --setBoot.

Or can it?

The code that embeds apfs.efi into the container's EFI is actually outside the block that actually sets the current startup drive. Which means that action will occur, regardless of whether there's an error.

So, by using an option that generates an error, --setBoot, we can get the EFI modified as needed. Adding --nextonly helps to minimize any potential side effects, too, since that just sets up the next boot without making the selection permanent (and doesn't do it anyway, since doing that requires privileges we don't have).

And, indeed, that solves the problem.

Spock Would Not Be Pleased

I'd argue that embedding the apfs.efi into the container's EFI should be done during the regular bless --folder operation, since the drive really isn't fully blessed without it, but I'm sure Apple had a reason to do it this way, even though it seems...illogical.

But logical or not, the multi-day investigation resulted in a workable fix, which will be in the next Beta, and obviously in the final release of v3.0 as well.

Back to it. Have a good weekend.

Can You Dig It? Wednesday, October 04, 2017

A few days later, and we're back with another beta. But not with a lot more sleep, so I'm afraid we're going to have another relatively dry and factual post. With barely a parenthetical. No asides. Hardly any wind-up. Just the facts and nothing but. Pitched right down the middle. Put out there for you. Right in front of your face. No need to scroll. Hardly a word out of place. Nothing wasted. Not a single ounce of fat. Lean, tight prose.

Get to the Point

We've done a bunch more internal work on this beta, so (in general - hah! got a parenthetical in there) it should be cleaner and more functional for all. Specific changes include:

  1. Erase, then copy now works with APFS When you're copying APFS to APFS, you can now use Erase rather than Smart Update, if you want to (or need to, because you're unregistered—but please register).

  2. Improved bootability We've improved some edge case handling for some boot configurations.

  3. Fixed non-expanding main window & copy now button In some configurations, the main window wouldn't expand, the copy now button wouldn't work, some elements of UI wouldn't reflect the current pop-up settings, etc. The root cause for all these problems has been fixed.

  4. Drive UUIDs no longer shown instead of the name in some fields That's right, you didn't name your drive 3443-93YDAE-8834F-007EEDA, we goofed.

  5. Source pop-up shows the size again And all is right with the world.

  6. Better logging Mostly to help me when I'm helping you, which helps you, and me. Win-win.


We had a few reports from people who were getting a very weird error during the bless process: they'd get a file not found error, and the backup would abort. With the help of some willing users (apologies and thanks to Jeff, Mark, Glen, Bryan, Michael and Paul), we thought the common element was FireWire, but then someone checked in with the same case with USB.

So we ruled out FireWire and pursued a bunch of different things, none of which worked.

Until we determined that the USB guy was having a different problem. Which meant all the others were FireWire. So, we asked for those who could to take the same drive, switch to USB, and Smart Update the result and... it worked.

Unbelievably, High Sierra won't bless APFS on FireWire, at least in its default configuration. We're trying to see if we can come up with a way around that, but until then, connect your FireWire drives via USB or Thunderbolt.

End of an era, folks.

UPDATE: We're having success with FireWire in-house, so it's definitely not all FireWire configurations. We're still trying to figure this out.

Just the Tips

Some things to keep in mind:

  • If you've just turned on encryption, your backups can't be performed until the encryption process is complete, since snapshots are disabled during the encryption process. So, sit back and let the encryption magic happen...then back up.

  • Please install SuperDuper! when you're an admin. Otherwise, the Quarantine attribute can get stuck on. Note that it's often easier to install by running SuperDuper! from its download image: it'll offer to install itself.

  • Don't convert a backup volume from HFS+ to APFS. Instead, erase it using the steps in the previous blog post.

Stop Yer Yappin'

See? Short post. Going to sleep now. Download away:

SuperDuper! 3.0 B3

Murtaugh’s Lament Sunday, October 01, 2017

It's been a bit less than a week since High Sierra's release, and we've been busily updating SuperDuper! v3.0 Beta 1 to Beta 2 (which, per the usual custom, is available at the end of this post). Our thanks to all the users who took the time to download the first beta and provide feedback: it's been really helpful to have the additional coverage as we work to wrap up v3.0.

We've been really pleased with the way snapshots have been working with the new version. We haven't seen a single report of a problem due to highly active files: it's doing just what it's supposed to do, which is great. Doing it this way is going to really improve people's backup experience.

Sorry for the lack of jokes in this post. It's been a long week, and my punch-up crew is on braincation.

(Note that after a version of this post went up we found a better fix for one of the issues below; if you downloaded B2 at that time, please download and install it again.)

Format Change

A lot of people have been confused about how to format their backup drive as APFS, and are confused about how to get an HFS+ volume on the same drive as an APFS volume.

The new Disk Utility has some nice features, but they've buried a bunch of stuff in the UI. Here's how to do both.

Format the Whole Drive as APFS

  1. In Disk Utility's "View" menu, "Show all devices".

  2. Select the drive hardware, above the existing volume, in the sidebar.

  3. Click the Erase button.

  4. Choose the "GUID" partition scheme, and the plain APFS format.

  5. Erase the drive.

Add an APFS partition to an existing drive

  1. Select the external drive in the sidebar

  2. Click the Partition tab

  3. Click the "+" button below the partition diagram

  4. Size the volume as needed

  5. Choose the APFS format

  6. Click Apply

Add a new APFS volume to an existing APFS container

  1. Select an APFS volume in the sidebar that's in the container you want to add to

  2. Select "Add APFS Volume" from the Edit menu

  3. Select the options you want, including minimum and quota sizes if desired, and click Add

Now that you know how to do that, let's discuss SuperDuper-specific things.

We Go On Three?

Overall, the feedback has been quite positive, and I'm pretty happy with how v3.0 is working for most people, but (as expected - it's a beta) there are a few areas where we needed to either work around High Sierra weirdness, or fix our own bugs. Namely:

  1. Copying from APFS to HFS+ fails

    Three interesting things happened here. First, there's a special hidden folder on HFS+ called ".HFS Private Data^M" that we automatically ignore during a copy, since it's managed my HFS+ and is unique to the volume. And yes, it has a ^M character at the end of the name.

    Weirdly, when High Sierra converts an HFS+ volume to APFS, it retains this particular folder, even though it's no longer something that's needed. And, on top of that, trying to match the name, with the ^M, fails with APFS "globbling"...and thus we copy the file.

    Going APFS->APFS, this works fine, since the folder is just a folder. But going APFS->HFS+, we get an error, since it's not ignored (due to the APFS bug) and can't be written (because it shouldn't be copied).

    We've worked around this in the new update.

  2. There's no Preboot when going APFS->HFS+

    A last minute change caused us to try to bless the Preboot volume when there wasn't one, since HFS+ volumes don't have preboot. Although we continue to recommend copying APFS to APFS, as discussed in my previous post, this is now fixed.

  3. Errors when using Erase, then copy

    Alas, erase copies of APFS volumes are failing when finalizing Preboot and Recovery. This happens because of an issue discussed in the previous post: the UUID of the volume changes during the erase, but we're copying the Preboot and Recovery based on the old UUID value, so they can't be found.

    We didn't catch this because while we checked Erase with non-bootable volumes, to save time during our test pass, we stopped the bootable volume test and then checked Smart Update (since we were now going from the erased volume, and the previous erase tests passed). Dumb, and the test matrix has been updated to ensure it doesn't happen again. This will be fixed in the next beta: in the meantime, use Smart Update.

  4. Crash with disk images

    Another last minute regression (as we rolled back the image handling we didn't finish, mentioned in the last post). Fixed in the new beta.

    Remember, though - if you're copying APFS volume to images, please open/mount the image first and copy to its mounted volume with Smart Update, rather than to the file.

  5. Visible Snapshots

    We consciously show the snapshot during the beta for debugging purposes, which confused some users. Given the good results we're seeing, they're now treated as release-ready, and are hidden.

  6. Can't Create Snapshot

    Two users had an interesting problem where the system returned that snapshots couldn't be created. It looks like this happens when the source drive is being encrypted but the process isn't complete. It's a very rare issue, given the number of testers, and the amount of coverage. We're continuing our investigation, and trying to reproduce in house.

    If you're seeing this, and you haven't already contacted us, please get in touch!

  7. Resource Busy error when updating Recovery

    There are some interesting aspects to this particular problem. Based on the error, this should mean that the Recovery volume is mounted somewhere else, and we're trying to double-mount it. But we've checked for that, and it's not mounted anywhere else.

    As we were further working through the case with some users who had it happen (we've never seen the problem in house), we also saw situations where some of the files in Recovery were busy during pruning, and thus couldn't be removed.

    So, we came up with some clever workarounds which we've implemented in this version. They seem to work for our in-between-beta test users who hit the issue.

    As much as we've love to say "problem solved", we're continuing to gather data, since it doesn't make a lot of sense, while also logging additional diagnostic information in case it does happen to the broader test group.

    It's important to note that when this fails, your data has been backed up successfully, and you can restore: you just might not be able to boot from the backup. If you're stuck, as always, get in touch.

  8. Various and sundry items

    We fixed some problems caused by special characters in volume names, a few UI and log typos (no, we don't know what "Ingnorning" is either), updated the signature so it should open normally for all users, and the like.

Exit, Stage Right

So, that about does it for the Beta 2 release. Thanks again for helping out with the testing, and drop an email if you're having problems.

SuperDuper! 3.0 B2

Cheat Sheet Monday, September 25, 2017

Told you it wouldn't be long until I posted again.

Spoiler Alert

We've finished up a bunch of internal testing over the past few weeks, and there's a beta of SuperDuper! for High Sierra and APFS linked at the bottom of this post. But it's so exciting, in a totally nerdy way, that it would be a mistake to not follow the whole story, with its twists and turns. So let's dive in.

Our Antagonist

As I mentioned in the last post, APFS is basically undocumented. That required us to make certain assumptions about its capabilities, and to draw inferences from what's on-disk in order to produce something that replicates the source.

APFS volumes are hosted in a container, which is basically a GUID partition on a drive. That container has a pool of storage which is shared between all the APFS volumes in the container. So, in a 1TB container, you could have a large number of volumes, each of which can draw from the 1TB of storage available in its container.

Only APFS volumes can be in the container: HFS+ volumes are not allowed.

In addition to the startup volume, and any volumes that you create yourself, a container that hosts bootable volumes also contains three hidden volumes with special "roles". One, called Preboot, contains all the information required to start the boot process. Another called Recovery, is the recovery volume. The third, VM, is where swap files are stored.

These volumes are minimally documented in the asr and diskutil man pages (the asr page actually discusses what makes up a valid system), so we're quite confident about what we've done in terms of the volumes and their roles. Unfortunately, their contents are not, and so here is where we've made assumptions. Also, since we can't create our own volume contents, we copy that data from the source's equivalent volumes.

Papers, Please

Both HFS+ and APFS volumes have their own unique ID (UUID). Each special volume mentioned above associates various information with the unique ID of the corresponding bootable, role-less APFS volume. Unfortunately, those unique IDs cannot be preserved across an erase: they're read-only. As such, there's significant housekeeping involved in maintaining these special volumes, and in positively identifying the volumes you've selected as the source and destination.

On top of that, the reboot and recovery data can't just be copied whole from the source, because multiple bootable APFS drives in a single container share the same special volumes... so, as you might expect, there's also new logic involved.

This all works its magic behind the scenes, and you shouldn't notice any changes...although you might notice some subtle improvements.

There and Back Again

As I mentioned in the previous post, we allow APFS to HFS+ copies (and back). However, copying from HFS+ requires the special volume contents to be stashed on the backup copy, since HFS+ volumes don't have all these special role volumes (and their partition schemes don't allow the same kind of 'guaranteed' partition creation). That's something we don't do in this first beta.

In addition, given the full extent of APFS's capabilities are not known, we're not fully confident in allowing this type of copying in our beta, and discourage the use of HFS+ to APFS copying. If you need to restore HFS+ to a bootable APFS volume, reinstall the OS to a clean volume and point to the backup when prompted during first boot.

And When You Smile for the Camera... (RIP Walter)

Ah, but these stories always have a twist! We think this is a good, Unbreakable twist, too.

One of the challenges of copying a live volume is that it's active and always changing. Even as we're stepping through the data, the user could delete files out from under us, change the data...almost anything can happen. In general, it doesn't. But it could. That's why the User's Guide suggests quitting applications before copying.

One awesome thing that APFS has is the ability to create "snapshots" that freeze the state of an APFS volume. Copies from the snapshot will exactly match the state of the source at the moment the snapshot is taken, so you don't have to worry about what applications are open, what might be written or deleted in the meantime, etc.

Snapshots have a lot of capabilities that were mentioned during the WWDC session, but most of those aren't yet available to developers. However, the ability to actually create and copy from them is both available and documented! So...

We're really happy to announce that SuperDuper! uses snapshots on APFS boot volumes when copying. Copies should be much more reliable and less error prone, and (as usual) the whole process happens completely transparently to you, the user.

To get this to work, there's literally nothing you have to do: no settings, no muss, no fuss. If your startup volume is an APFS volume, the details are all handled for you.

Continuity Errors

Apart from special-volume-stashing, we weren't able to finish implementing one thing in time for High Sierra's release: backing up to unmounted images. This also has to do with the special volumes mentioned earlier: when a volume isn't available, we don't know its format, nor do we know whether it requires volumes to be created.

We didn't want to mount the volume to find out, and there were so many cascading cases involved we decided to not release that part of what we've done. Instead, once you've created an APFS image backup, open it in Finder by double-clicking, then copy directly to the mounted image's volume. That'll create the special volumes so it can be properly restored.

You may also notice that we're copying a bit more than you'd expect: we see it too. We decided it was better to copy a little more than necessary than a little less, since it's just a matter of time taken and not overall fidelity. This will be improved in the final release.

The main application is now 64-bit, but the copy engine is still 32-bit. We didn't want to potentially destabilize the copy process by including our alpha-level 64-bit copy engine in a public beta, so we're 95% 64-bit, and 5% 32-bit.

Finally, there's a black window flash during animations that's related to the 64-bit changes. It's ugly. We know. But it's not a blocker, and there were more important things to get working (snapshots!) so, think of it as a brief moment to consider your place in the universe and...enjoy?

Dinner is Served

Since it's a beta, dinner is dog food. We've been eating it for a while now and it's delicious, but given FDA standards for dog-vs-people food, there may be a higher quantity of insect parts in your portion.

OK, that's kind of gross.

What I mean to say is that we've tested this internally, and we're pretty pleased with how it's working.

That said, we're talking about a brand new OS with a brand new file system and some brand new capabilities. This version is a beta, and while you can continue to use it as you normally would, you may encounter issues.

These things happen.

So, in conjunction, also use Time Machine as an extra backstop (always a good idea). I'm here for you at the support email; let me know if you have any problems.

We'll be working to move this from beta to final release as we finish up some of the remaining tasks, and the inspectors determine it's fit for human consumption. We might even get a chance to sleep a little. Probably not, though, so if any support replies are incoherent, please be understanding.

In the meantime, thanks for your patience and support: it's truly appreciated.

Download away!

SuperDuper! 3.0 B1

News on the March! Wednesday, September 13, 2017

It's inevitable—another year, another macOS version (I am still not used to typing "macOS"), and another build up to a significant SuperDuper! release. Sorry I haven't been blogging the whole way through, but it's been busy, and I just haven't had the time.

As of this morning, we have a release date - September 25th. So, for those asking (and there are a lot of you), let's talk about High Sierra. Lucky 13! Woo!


First, we'll definitely be supporting APFS. That work has been in progress for some time, and continues as of this post. We already have copying to and from APFS volumes working "in the lab", as it were, and testing is ongoing.

The bad news is I'm not confident enough to say we're going to release our APFS support day-and-date.

I know this kind of hedging is disappointing. But it's important to note that Apple still hasn't released any documentation on the "proper" way to create a bootable APFS volume. An example of what they have in mind was released for the very first time when the High Sierra developer release came out a few months ago, but that's it. We basically have to make an educated guess about what they want.

We've designed and implemented that, and it's significantly different than HFS+'s boot setup, with various special partitions dedicated to specific purposes (even a separate VM volume!), and entire new volume management system, etc.

So, we have both copying and boot working, and we're testing it carefully to try to cover all of the various permutations that can occur. Because no guidance or documentation is available, and the process is all reverse-engineered from existing volumes, it's difficult to know what might happen in the future...and protecting against mistakes, and informing users what their potential actions mean, is really critical.

For example, what happens if you do an "Erase, then copy" from an HFS+ volume to an APFS volume? In our current version, we match the format of the source when we erase. But, HFS+ can't be in an APFS container. So, we'd have to convert the container to a regular GUID partition. And since there might be other APFS volumes in that container, you'd end up destroying them.

Not good. And that's just one case.

So, we're being cautious, knowing that users who have continually followed our advice (namely more backups are always better than fewer, and use more than one backup program, such as SuperDuper! and Time Machine rather than either on its own) will still be covered by Time Machine if they jump the High Sierra update as soon as it becomes available.

But what about HFS+?

Yes, making a backup from APFS to HFS+, and booting off that, can work as it always has (once our APFS support is released). And HFS+ to HFS+ works as expected as well, save for a few small issues in 2.9.1.

In particular, Apple has further tightened its System Integrity Protection process, and is completely denying access to some files on the startup volume, even when copying to a non-startup volume. We consider those errors ("Operation not permitted") to be fatal in 2.9.1, and so we stop. We have a simple, preference-based workaround for this that we've provided to people during the beta on request, and 2.9.2 has it built-in. (This is the kind of thing I'm talking about when I said "it's difficult to know what might happen"--we didn't know what could happen with SIP, and so we planned for possible changes.)

But since APFS is, again, basically undocumented... what could that backup be missing? How will changes like filename normalization affect future copies if a dot-update modifies behavior? How do you make a snapshot, since that is obviously intended to be a better source for a backup? And do androids actually dream of electric sheep?

These are the kinds of things that have been keeping us awake at night at Shirt Pocket HQ. I feel like I've aged as much as a two-term President.

Anyway, we're grinding through this all as quickly as we can. We don't want to finish until we're sure we have the shipping bits, because, unlike with earlier OS versions, we're dealing with an entire new file system. We'd rather be late than wrong.

We're probably not wrong, but we want to be sure.

Automatic conversion

Speaking of being sure, one of the scariest part of High Sierra is the fact that, if you have an SSD, you'll have no choice: you're going to be converted to APFS, whether you like it or not. Apple is obviously confident about this process, or they wouldn't do it, but even if the conversion is successful, it's important to note that while that means it worked from their point of view -- conversion accomplished! -- this changeover won't be without pain.

  1. Your existing, valuable low-level tools, such as Disk Warrior, will instantly be rendered useless. In a pinch where Disk Utility can't fix it? Tough luck.

  2. Want to host an HFS+ volume on your drive? You can't in an APFS container.

  3. APFS doesn't seem to be faster than HFS+ (which is not to say it won't ever be, or that it won't be more stable...a low bar, I know). That cool demo where copying a whole directory is instantaneous? That's because the data isn't really being copied. It's being referenced, which is, of course, fast. Copying happens when you modify, so it's basically being done "lazily".

    But think about it. That also means that if you made a copy of your data "just in case", and you developed a bad spot on the drive, all copies of the file are now damaged, because they share the same data. Disk damage can now cascade across far more files than before, because you can't tell what's shared. Even snapshots can't save you if they're referencing the same bucket of damaged bits.

  4. So many other things.

There are going to be growing pains here, and a lot of it will be for long time developers who have been doing invaluable work for years, and unlike us, they have to start again from scratch. Need I say they deserve your support and encouragement?


I'm also getting a lot of mail about our 64-bit plans, since there's been a pile of confusion coming out of the WWDC announcements, so let me try to set things straight.

High Sierra works fine with 32-bit apps. Come January, the App Store will stop accepting 32-bit store apps. And, at some point in the future, Apple will stop supporting 32-bit apps.

Now, for most apps, there's really no advantage to being 64-bit (save for some really minor system-wide memory benefits, which—frankly—were the other way around when 64-bit APIs were introduced, and no one complained about that). So for many developers this will be a lot of unnecessary work, with no end-user benefits.

All that said, while there's no rush to do so (they're not phasing out 32-bit for a while), our full High Sierra release will be 64-bit, so you can rest easy, knowing that we'll be ready for the actual phase-out well before it happens.

Should I Update to High Sierra?

I think I usually tell people to "take it slow" with an entirely new OS version. While there have been "huge win" updates in the past (10.6 is a great example), High Sierra isn't one of those.

Rather, while it may be a good (or even great) update over time, it also has the potential to destabilize things far more than anything that's come before. It's going to be hard to judge its impact until its wide release, and even then, it'll be a while.

If you're a normal user, I would strongly encourage you to not update to High Sierra right away. Let others take the risk. Wait until things calm down and the initial problems, which are inevitable, are fixed. Continue doing what you've been doing before High Sierra: you're not missing anything of significance.

Apple's going to be OK if their "adoption graph" doesn't go straight up in the air.

After all, why should you be a statistic when you have work to do?

But I Want to Update Right Away


I Insist on Updating Immediately!

Sigh. OK. But don't say you haven't been warned: we don't all float down here.

Before you update, use SuperDuper to make a full backup or two. Check your backup by starting up from it. Then, unplug the backup drive from your Mac and put it somewhere safe.

As I've recommended elsewhere, you should be making multiple backups with other programs as well, including Time machine. So, after you update, continue to use Time Machine to back up. Given it's basically written by the same team as APFS, and Apple knows what is and isn't possible, even when they don't document it externally, this is your best bet to start with.

If you need to roll back to your previous OS, you cannot just use Smart Update. In fact, you also can't use Erase, then copy, because your internal drive has been converted to a storage scheme that won't work with anything earlier than High Sierra.


So, after starting up from your SuperDuper backup, use Disk Utility to erase the drive you want to restore to, by selecting the drive hardware above the volume, not the volume itself. That will roll you back to something that can properly host HFS+ and boot pre-High Sierra releases. You can then restore your SuperDuper! backup normally, using "Restore - all files" and "Erase, then copy" or "Smart Update".

But How Do I Back Up?

For the moment, as I said above, use Time Machine. Apple's teams know the details of APFS, and as such Time Machine isn't in the "limbo" we're in with regard to ensuring things are as they should be. Remember, disk space is cheap, and I know I say this too much, but it's true: no one was ever sad they had too many backups.

If you are running High Sierra with HFS+ (namely, if you have a spinning disk or Fusion drive), our just-released SuperDuper update will work fine. Use that in addition to Time Machine.

Our full, APFS-supporting version (with some other surprises) will be out as soon as we can get it finished. And we'll have a public beta when we're confident enough to put it in your hands.

This is Going to Cost Me a Ton, Isn't It.

Actually, no. Since 2004, we've never charged for SuperDuper updates, and our High Sierra update will be free of charge as well.

Clearly, we were dropped on the head as babies.


So there you go. I'll be back relatively soon with more.

SuperDuper! v2.9 - anti-AntiVirus (+ macOS Sierra) Wednesday, August 31, 2016

Hi, everyone!

I'm happy to say that we're releasing SuperDuper! v2.9 today, at long last. In fact, if you're reading this, it's out. Hooray!

This new release has a large number of enhancements and bug fixes that improve SuperDuper!'s responsiveness and performance. Many of these are longstanding items that required a significant amount of investigation, across many different systems, to diagnose and fix, so we're really grateful to the users who reported the problems and were willing to work with us to run down the underlying issues.

But rather than talk in detail about each (you can get the list of changes in Help > Release Notes), I want to discuss how SuperDuper! interacts with the bane of every copying application: Antivirus programs.


Antivirus programs are getting more popular on the Mac, even while the threat environment doesn't get worse. And they're extending their reach, protecting against things like "phishing" emails. Plus, all Antivirus vendors include non-Mac threat signatures (mainly Windows applications) in with their Mac-specific applications, which tend to flag things that aren't really relevant.

The result of all this (beyond slowing copies down) is that Antivirus users are being informed of potential threats constantly, and before v2.9, each of these pseudo-threats would cause SuperDuper! to stop, because they're flagged as errors (specifically, "Permission Denied" errors) when we try to open the file for copying.

The vast majority of these files are in Junk mail folders. Due to the way Apple Mail (and similar applications) work, those files are cached locally. So, even though the user isn't really interacting with the mail, the files are on disk and copied, and that causes errors to happen much too often.

Given that error isn't Antivirus-specific, we've been reluctant to ignore them: our philosophy has always been to stop on errors (see the "I/O Error Handling" post) But, as more users install the apps, we've decided that the frequency of non-Antivirus related "Permission Denied" errors is so low (I haven't seen one in more than two years), the risk of ignoring these particular errors is minimal.

So, we've added a new preference -- which defaults to ON -- that ignores "Permission Denied" errors. We do log any occurrences, but we don't fail the copy.

This should significantly improve the lives of less technical users (or even technical ones who have Antivirus program use mandated by company policy).

macOS 10.12 - Sierra

To answer the inevitable question, we've been testing v2.9 on current Sierra builds, of course, and initial compatibility is looking good. Remember, though, Sierra is in beta. We do not have the final version to test against, anything can happen between now and Sierra's release, and as such we can't guarantee that we'll be fully compatible with the official, release version of macOS 10.12 until that happens.

Along similar lines, we're not (yet) APFS compatible. The documentation for APFS is still quite sparse, and given that it's in very early preview, we decided it was unwise to release an initially compatible version until it's a bit better documented and closer to done. (It's much easier for us to be pretty confident about the stability of the 8th beta of Sierra than these early releases of APFS.)

In the meantime, though, enjoy the new version, and don't hesitate to contact us if you have problems.

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