Yes Virginia, the Mac sometimes needs a reboot. The problem I just had was bizarre. I use a network drive as the Time Machine target for my MBP, and it stopped working yesterday after we had a brief (seconds long) power blink. It was enough to reset the router though, and that took out my network for a brief period. When it came back, the MBP couldn't see the remote drive, even though it could see the Mac that the drive is attached to, and said Mac had the drive mounted, and claimed to be sharing it.

Now, maybe there's something I could have done short of rebooting, but I figured a clean reset would fix the problem - and it did. Having said that, there was something I had to deal with manually in order to get Time Machine to function again.

When you use a remote drive for Time Machine, backups are stored in what the mac calls a "sparse bundle" file. On the outside, it looks like one file, but it's basically a disk image of a file system. When Time Machine starts a backup, it mounts it, creates a new backup directory in the mounted image, and gets to work. It calls the new directory "...InProgress", where the "..." is a timestamp. After it finishes, it renames the directory without the "inProgress", and unmounts the image. Here's the upshot: if Time Machine gets interrupted by a network outage, that "InProgress" directory stays there under that name - and any new backup attempt will fail, as it thinks a backup is already in progress.

Fixing this was harder than I thought it should be - here's what I did:

• Using DiskUtility, I mounted the sparse bundle on the host Mac. To make this not take forever, I had it skip the validation
• Moved the "InProgress" directories to Trash - backups could proceed after that
• I couldn't seem to empty the trash with the Finder, so I opened a shell, did a "sudo sh", and then went into the .Trash directory in the disk image, and executed an "rm -rf". That did the trick. I think the Finder would have done the job, I just lost patience with how much time it was taking. The "rm -rf" took awhile.

It occurred to me afterwards that I probably should have tried simply renaming the "InProgress" directory to match the pattern Time Machine uses - I'll give that a go next time it happens.

Now Listening to: Darkness On The Edge Of Town by Bruce Springsteen from: Live 1975-85 [Disc 2]

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