Things You'll Need:
- Disk Warrior (optional)
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Step 1
Before we need to do anything, we need to shut down time machine. The fact that you're having this problem means time machine won't mount anyways, but that could change half way through the process. We don't want it trying to build a backup or some other crazy business while we're working on it. Go into preferences and throw the giant switch to the left to shut it down.
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Step 2
Open up Terminal and type in
hdiutil mount -nomount -readwrite /Volumes/TM/xx.sparseimage
Where /Volumes/TM/xx.spareseimage is the full path location of your sparseimage. If you're not so familiar with the Terminal, a quick trick to get the full path is to just type in the hdiutil mount -nomount -readwrite part and then drag the image from finder into the Terminal window. -
Step 3
Now that we've attached the image, we can repair it. There are two ways to do this - Terminal and DiskWarrior. Because not ever one has Disk Warrior we can try Terminal first. If you do have a copy of DiskWarrior, skip this step and do the next one instead. Assuming you don't have DiskWarrior or insist on using Terminal for some reason, let's give this a try. Enter this command:
fsck_hfs -rf /dev/disk1s2
That will attempt to rebuild the filesystem catalog. Given that this is over a network, it could take an obscenely long amount of time to process and repair. Depending on the size of your drive we're talking several hours. -
Step 4
Assuming the last step didn't work (or you skipped right to this one) fire up DiskWarrior. Under the DIrectory option, select your backup and hit the Rebuild button. After a bit of work on Disk Warrior's part your Time Machine backup will be restored! Exit out of here, open preferences, and turn Time Machine back on. If it continues with a backup, everything is fixed. If it refuses to backup, your image is permanently corrupted and can't be fixed. You'll have to delete it and back up all over again.
