Something crazy is going on with Time Machine. I upgraded to Mavericks yesterday with no issues. After performing a final backup on Mountain Lion, I disconnected my backup drive out of an abundance of caution, just in case I wanted to use it to roll back to 10.8. I plugged it back in today and let it do its thing, and got an out of space warning. I wasn't too worried about this, since I had been getting these previously (in the past, TM didn't do the best job estimating the space required and removing old backups).
Upon investigation, I discovered that only the most recent backup (from before the upgrade) was available. I double checked this in Finder and Terminal to confirm, and it appears correct. The Time Machine preferences showed the last backup as October 6, which seemed a bit more reasonable, but I saw no evidence of those files actually existing. The only sure thing I could determine was that something was taking up a lot of my backup volume — out of a ~750 GB volume, only 50 GB was free (Time Machine is estimating 154 GB needed, although only ~140 GB are used on my boot drive).
After further digging, I discovered what was taking up all the space. The hidden
.RecoverySets folder, within the
Backups.backupdb folder on my Time Machine volume. In it are more than 1,200 sequentially numbered folders, each with a
com.apple.recovery.boot subfolder, containing a 419 MB
BaseSystem.dmg file. Based on the md5 hashes, these dmg files are all identical, and in total add up to nearly 600 GB (or, the vast majority of the space on my Time Machine volume).
- Missing Time Machine backups after 10.9 upgrade. Don't appear in Finder or Terminal.
- Lots of folders in
Backups.backupdb/.RecoverySetstaking up the majority of space on my TM drive.
- 2012 iMac running 10.9 (release build, no developer previews), upgraded from 10.8 via standard App Store install.
- Time Machine drive is an encrypted volume, with another volume on the same drive used by SuperDuper (which appears to be unaffected).
- Are my old backups completely gone? (I'm thinking yes.)
- What are the folders within the
.RecoverySetsfolder, why have they been gobbling up space, and what can I do to prevent it in the future?
- What do you suggest I do now for Time Machine backups? I'm leaning towards scrapping it altogether and starting fresh, but I am concerned about running into this issue again.
I'm not terribly concerned about the data loss at the moment — I have two other separate backups — but I do want to ensure the integrity of my backups in the future. Any info you can provide would be appreciated.