I have a Mac and I use Time Capsule, which is an amazing device that provides WiFi, automatically backs up your computer, and can be used as an external harddrive.

But it stopped working on Thursday giving me the error message, “The backup was not performed because an error occurred while copying files to the backup disk. The problem may be temporary. Try again later to back up. If the problem persists, use Disk Utility to repair your backup disk.”

I tried a bunch of different things including disk repair, removing the last partial backup, and connecting the computer directly to Time Capsule. But then I remembered that I was messing around with my directory structure around the same time that my backups started failing. In fact, one of the things I did was to replace a symlink to a directory with a copy of the directory.

That turned out to be the problem. So if you have problems with your backup after replacing a symbolic link to a directory, try renaming the copy to something different first.