Unmountable Sparse Image

[diskinserted]

I recently made a sparse image of my old MacBook and stored it on my husbands iMac G5. It was roughly a 60GB file. We recently purchased a new Mac Mini and planned on cloning the disk image to the mini. When I double clicked the image, SD! told me that the image is unmountable. When getting info on it now it tells me that the image is now only 44MB and not the initial 60GB.

Is there ANY hope of retrieving any of that data?

[dnanian]

It sounds to me like that file was physically damaged between when you made the copy and you looked at it. Do you still have the G5 around?

You can *try* to repair the image with Disk Utility by dragging it into DU's sidebar, selecting it and using the Disk First Aid tab. But given that it seems to have been truncated by 16GB, it's not likely to work...

[diskinserted]

It didn't go down by 16 GB. It went from 60GB to 44 MB! The G5 was showing it as a 60 GB file until the minute I tried to move it over to the mini, at which point it gave me the unmountable message. Immediately after that, I got info on the dmg file, and it had it as 44 MB. I just don't see how the HD could suddenly see a drop of 59.9 GB. Should I assume that the file was corrupt from the get-go? I just don't see how it could be taking up so much real estate, then go to such a small size, almost instantly. I will try the DU repair and see what happens.

Is there any way, for future reference, that I can periodically check on a dmg file and make sure that everything is cool? If this is indeed lost, this is a BIG loss. I'd like to try to avoid it in the future. Would running something like Data Rescue work? I've avoided restarting the machine in the hopes that something could be salvaged. Why would it appear to have made that back-up only to have created a file bloated with nothing? Is there anything that can be done? DU showed

"Verify and Repair disk “disk2s2”
Checking HFS Plus volume.
Invalid B-tree node size
Volume check failed."

[dnanian]

Sorry, I mis-read 44MB as 44GB. Definitely sounds like teh image was physically damaged -- I don't see how it could happen either.

No, I wouldn't suggest it was corrupt from the get-go, since you had already looked at it being correct, no?

What I'd suggest is writing your backup directly to a drive, rather than to an image. That way, you can simply look at the files, and you won't have the (typically unnecessary) "indirection" involved with an image.

Since I don't know how a 60GB file could get whacked to a 44MB file, it's hard to know whether Data Rescue can help. But you can try...

[TMay]

Inserted...

A question. As Dave asked, I think, is the original machine still available to you (the MacBook?) Obviously, the data has been erased or you wouldn't be sweating the DI, but... If the machine is still in your hands, and if you haven't overwritten the data on the disk, you might have better luck running some data recovery utility there than running it against the damaged disk image file. Just a thought.