I recently had to restore a Mojave Mac Mini from Time Machine. It all seems to go well until I discovered that the Photos Library was gone. After looking through the TM backup, I see the last time it was backed up was 2018. I did nothing I can imagine to exclude it. It's un-backed-up state is confirmed on a second off-site backup started in Feb of this year; the file simply does not exist.

There are no TM exclusion rules that would have prevented the file from being backed up. Time Machine Exclusions

I suppose I'm out of luck on a recent version of the file, but why would this have happened? Unless I'm missing something, this brings into question whether TM is a viable tool for backups.


I decided to take my lumps and restore the old library. 17 GB of data is better than none. I did check the next time TM ran and it happily backed up the library! Note that I did not change any settings.

This gives me great pause in relying on Time Machine for backups. It archives many of the files on my disk, but if it misses even one, that is always going to be the one that you need.

Also of note, this is the only machine I administer that I don't use a belt-and-suspenders approach to backups. All my other machines have at least one TM backup plus a bootable backup with Carbon Copy Cloner. I just ran out of CCC licenses for this machine.

  • Might the folder have been excluded?
    – benwiggy
    Commented Aug 15, 2020 at 17:04
  • The only exclusions are the external disk itself and /Users/Shared/adi
    – Paul Waldo
    Commented Aug 15, 2020 at 17:06
  • I'm on a Mojave Mini, too, and it appears to be backing up the Photo library.
    – benwiggy
    Commented Aug 15, 2020 at 17:07
  • You haven't checked a backup in two years? Commented Aug 15, 2020 at 22:49
  • 2
    @MarcWilson is there a way to verify that every file on the source is contained on the backup? Many many files are indeed on the TM disk, hence the ability do perform a restore. What would let me know a priori to check this particular file on the backup?
    – Paul Waldo
    Commented Aug 16, 2020 at 12:21

1 Answer 1


Time machine constantly takes snapshots of each file, this simply is a lot of data, and being conservative is important for the sake of the consumer's end. Harddrive reads and writes are expensive! Especially when it is the eventual cause for a harddrive to fail and a critical system backup is therefore lost on the consumer's end.

Apple offers ~/Pictures/Photos Library to be backed up to iCloud by default, and is cutting a corner for saving your backup. Time Machine also doesn't backup many large system files that apple deems a "defaulted" file from macOS and easily reclaimed from remote apple servers.

Unrelated side-note: You can argue 5GB of free iCloud Storage isn't enough for even the Photos library alone, and you're right. But its incentive for you to pay for their service.

  • An interesting idea, but this feature is turned off on all the Macs in our household. I have verified that other machines with multiple TM disks are indeed backing up the Photos Library file.
    – Paul Waldo
    Commented Aug 15, 2020 at 19:16
  • 1
    When did Apple ever "offer ~/Pictures/Photos Library to be backed up to iCloud by default?" Be specific. macOS does not do any sort of backups to iCloud. iOS does. If you want to claim that iCloud Photo Library is a backup, please read support.apple.com/en-us/HT204264. Commented Aug 15, 2020 at 22:48
  • 3
    Almost every sentence here is wrong in some way.
    – benwiggy
    Commented Aug 16, 2020 at 14:09

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