2

I have tried searching for it but maybe I am not using the right words. tmutil does also not seem to have anything?

Time Machine started claiming that there was not enough space for the backup (I have been using the same HDD for about 1.5 years now). And true enough, only 50 GB are remaining, but incremental backups were much less than that. Turns out, when opening the Time Machine mount, there is no backup there, but when browsing the folder in the Terminal I can see

ls -lh /Volumes/TimeMachine/
total 8
drwxr-xr-x@ 3 root  wheel    96B Jan 22 01:46 2022-12-16-223342.previous
drwxr-xr-x@ 3 root  wheel    96B Jan 16 07:06 2023-01-08-153244.interrupted
drwxr-xr-x@ 3 root  wheel    96B Jan 22 00:46 2023-01-08-233410.interrupted
drwxr-xr-x@ 3 root  wheel    96B Jan 22 13:26 2023-01-11-102405.previous
drwxr-xr-x@ 3 root  wheel    96B Jan 22 13:37 2023-01-22-015014.interrupted
drwxr-xr-x@ 3 root  wheel    96B Jan 31 06:07 2023-01-22-144359.previous
drwxr-xr-x@ 3 root  wheel    96B Jan 31 06:01 2023-01-28-120137.interrupted
drwxr-xr-x@ 3 root  wheel    96B Feb 11 18:29 2023-02-11-125628.previous
drwxr-xr-x@ 3 root  wheel    96B Feb 12 23:24 2023-02-12-142959.previous
drwxr-xr-x@ 3 root  wheel    96B Feb 19 07:00 2023-02-13-101611.previous
drwxr-xr-x@ 5 root  wheel   160B Feb 19 09:17 2023-02-19-093419.previous
drwxr-xr-x@ 3 root  wheel    96B Feb 25 09:41 2023-02-25-023743.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 07:39 2023-02-25-073801.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 08:39 2023-02-25-083814.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 09:40 2023-02-25-093843.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 10:41 2023-02-25-103941.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 12:41 2023-02-25-123952.interrupted
drwxr-xr-x@ 5 root  wheel   160B Feb 25 13:41 2023-02-25-133958.inprogress
-rw-r--r--@ 1 root  wheel   1.4K Feb 22 15:19 backup_manifest.plist

but none of these are available in the Time Machine app or system settings or in the FinderEmpty Finder view. I tried removing the HDD as a TM location ('-' symbol in the settings) and re-adding it, but to no avail. Ideally, there should be some way to reconnect / reindex or something like that the backups that are clearly present in some form on the drive and then continue incrementally from there. The alternative would be to erase and begin again but surely this is not exactly what you have a backup like TM for.

Thanks for your help!

Some hardware details:

  • MacBook Air M1 2020 with a 512 GB SSD
  • Currently on the latest Ventura 13.2.1
  • External HDD (not SSD) with an AFPS Time Machine partition of 1 TB

The error appears to have begun over night two weeks ago, when suddenly the last backup failed because it tried to do a backup of everything, ignoring the previous ones.

7
  • 1
    If TM is complaining about space, then it's probably not space on your TM disk, but space on your system disk for snapshots. Check your free space and manage that, check and empty trash. There's likely a load of snapshots around for all those failed backup attempts. If necessary you can remove old ones with Disk Utility. Finder does interesting things to make TM backups not appear until complete so you will see different results in Finder vs Terminal. Feb 25 at 13:25
  • I like this idea and did not know about this! I found only a handful of snapshots from today. Did not touch them but deleted other files. There's now >100 GB free on my Mac HDD, but it still does not work and TM is complaining explicitly about the TM drive being too full. It appears from the wording that TM wants to do a full "first" backup, hence 50 GB on TM drive do not suffice. It ignores the previous backups, it would seem.
    – JNR
    Feb 25 at 21:50
  • Yes, you might need to bite the bullet and reformat the drive, though someone may know better. One point though, you say you've used the TM disk for some time.. is it formatted as APFS or HFS+ ? Spinner or SSD? Could you update your question with this and some hardware details, sizes, OS version etc? My own rule of thumb.. external SSD size = 2 * Internal SSD size. Feb 26 at 1:46
  • Snapshots get tidied up after 24h, but can grow quite large if there is a lot of churn on a disk. The snapshot view gives the 'private size', the size of each snapshot, and the cumulative size based on the amount of change there has been since each snap. Even if files & folders are excluded from a TM backup they still make their way into snapshots, which are volume based. So large files excluded can still cause problems later on if they persist in snaps, even if deleted. Feb 26 at 1:51
  • Thanks for the suggestion to add more details. It is AFPS-formatted classic HDD. The snapshots can't be the issue though if I now have 160 GB free on my internal SSD, right?
    – JNR
    Feb 26 at 10:14

1 Answer 1

2

Generally if TM is complaining about space, then it's probably not space on your TM disk, but space on your system disk for snapshots. I myself have been caught out by this before now.

To mitigate this one would check free space and manage that, check and empty trash. There's likely a load of snapshots around for all those failed backup attempts. If necessary you can remove old ones with Disk Utility. Finder does interesting things to make TM backups not appear until complete so you will see different results in Finder vs Terminal.

The local TM snapshots get tidied up after 24h, but can grow quite large if there is a lot of churn on a disk. The snapshot view gives the 'private size', the size of each snapshot, and the cumulative size based on the amount of change there has been since each snap. Even if files & folders are excluded from a TM backup they still make their way into snapshots, which are volume based. So large files excluded can still cause problems later on if they persist in snaps, even if deleted.

Since you've tidied up your internal disk (ref. comments) but still running into a problem with space, it now more likely to be there probably isn't enough space on the external drive. As you can't manually get rid of broken backups (normally the system manages them itself as part of a cleanup process) the safest thing to do would be to erase the disk and start a new TM backup.

Because of all the .interrupted and .inprogress folders it seems that the backup state is undetermined. In a healthy backup (on my machine at least), I only see a single folder corresponding to the last successful backup. The other backups are 'hidden away' by the OS, and only properly visible in Finder, or the TM restore utility. eg.

% ls -l /Volumes/Time\ Machine\ 2TB\ Grey 
total 48
drwxr-xr-x@ 7 root  wheel    224 26 Feb 21:06 2023-02-26-210632.previous
-rw-r--r--@ 1 root  wheel  20829 26 Feb 21:06 backup_manifest.plist

There are other ways to get to the earlier backups via the command line, but they, and macOS's behaviour when presenting them, are poorly understood by me and so I don't want to draw attention to them for the risk of getting it totally wrong. The UI is always the safest approach IMHO.

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