Backup without erasing?

[dnanian]

"Backup - all files" does, indeed, copy all the user files. It's "Safety Clone" that doesn't.

The main difference between the two is that while "Backup - all files" backs up / copies "all files" (as its name says), the "Safety Clone" copies the OS, and shares most applications and the user files by "linking" (aliasing) them to the original copies on the original volume. You can see this by examining the "Users" or "Applications" folders on the clone: they're filled with links/aliases. Those links point to the files on the original drive.

So, the Safety Clone is not a backup at all. It's a checkpoint of the system files, and lets you play in an "OS Sandbox" -- a safe place you can boot to and install updates. If you have trouble, you can roll back to the original by just rebooting. But since the User Files weren't copied -- they were shared -- any changes you made to your *own* data is still there, and up to date.

Make more sense?