Useful Article from Howard Oakley About How Snapshots Can Get Out of Hand


Do you have to actively manage snapshots?
If so, how often do they require your intervention?

  • No, they take care of themselves / what’s a snapshot?
  • Once a year
  • 2+ times a year
  • Once a month
  • Once a week
  • Every day

0 voters

Which backup program creates the problematic snapshots?

  • As above, no problems
  • Time Machine
  • Carbon Copy Cloner
  • Arq Backup
  • Super Duper
  • I create my own with tmutil
  • Other

0 voters

The non-functioning snapshot management of macOS Big Sur is even more pathetic than the fact that I still have to reboot every second time I boot my MacBook because macOS somehow forgets about all app permissions.

I have run into the situation several times where Time Machine would accumulate snapshots over a “longer” time period (1-2 weeks) during which it could not back up - e.g. during holidays. It doesn’t matter if no Time Machine backups were run during that time frame (i.e. holidays abroad), or if TM could only backup to my drive at home, but not to my secondary TM drive which I store at work.

The snapshots would silently eat up all disk space until 0 MB are left. Then macOS crashes, because, you know, no disk space left. It doesn’t even really “crash”, but it becomes unusable, apps cannot be opened or closed etc.

After rebooting, my Mac then crashes at startup. Absolutely ridiculous! I enter my password, the progress bar progresses a bit, then stalls, my MacBook gets super hot and then it reboots again. And again. And again.

The only way out is: CMD + R, mount local disk, open terminal, manually delete Time Machine backups. Took me several hours to isolate and solve that problem. I don’t even want to know how many people had to send in their seemingly broken MBPs to Apple or go to the Genius Bar, if available, and how often people were told they had to wipe and reinstall because something is broken…

I immediately sent feedback to Apple the first time this happened, but they did not bother to fix this even half a year later. I haven’t dared to not actively manage my snapshots during extended periods without access to all TM drives.

edit: Just happened once again. I made the grave mistake of just rebooting without first checking available (free) disk space, which was at only about 28 GB. That’s apparently not enough to boot for macOS Big Sur (all current updates installed). Needed to manually delete snapshots via Terminal from Recovery Mode. Sucks.

edit2: Now I suddenly have 400 GB of free disk space. I have not cleaned up anything manually except for a few snapshots to be able to boot again, which resulted in a total of 50 GB of available disk space. Maybe Apple wants to push me towards a 4 TB drive next time, but I’m sure they would manage to fill that up, too.

Only time I ever really had to worry about that is when using some really janky software (yes, I’m talking about you Kia Navigation Updater, written in Qt of all things). Oh, and that time when I wanted to get the Monterey beta last summer but the installer kept insisting that there’s too little disk space.