I had 11.6 Big Sur on an apfs volume, installed 12.0.1 Monterey on a different volume, deleted the first volume

Now Time Machine Backup fails:

Time Machine could’t complete the backup to “…”
An error occurred while preparing the backup.
Button: OK
log show --predicate 'subsystem == "com.apple.TimeMachine"'
2021-11-12 15:51:19.822567-0800 0x1ed985   Error       0x0                  230    0    backupd: (TimeMachine) [com.apple.TimeMachine:General] Backup failed (301: BACKUP_FAILED_PREFLIGHT_STAGE_DATABASE_GENERATION)
2021-11-12 16:34:53.380762-0800 0x1f0581   Error       0x0                  230    0    backupd: (TimeMachine) [com.apple.TimeMachine:EventCollection] No event store UUID for volume  '/Volumes/Recovery HD'

Key log output: No event store UUID for volume '/Volumes/Recovery HD'.

It seems Recovery HD has some storage uuid that is no longer available

What’s the action?

1 Answer 1


Recovery HD is a macOS 10 Catalina remnant hfs+ partition that macOS 12 apfs Time Machine cannot back up

for macOS 12 Monterey, apfs recovery is inside the apfs container

Delete or Erase Recovery HD using Disk Utility and Time Machine will work again

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    Commented Nov 30, 2021 at 18:18
  • This was indeed the source of the problem in my case! I didn't have to erase the 'Recovery HD' partition though, I could simply add it to the Time Machine exclusion list (Time Machine > Options > +, and add Recovery HD).
    – merlinND
    Commented Nov 9, 2022 at 15:20

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