Time Machine Drive Corrupt? - Can't Delete Backups, APFS Problem

[rm5]

Hey all,

I wanted to know if in fact my backup drive is corrupt. When I try to delete the old backups I don't need (just to clear some disk space), they move to the trash, but then they "restore themselves" when I eject and remount the drive. I've got hourly backups going on this thing, so maybe that's why it can't delete the backups—because it needs the "starting data." Also, when I try to delete the APFS volume of backups AFTER deselecting the disk for use in Time Machine Prefs, it fails to delete, saying it can't unmount the volume, although I can literally unmount it right there in Disk Utility.

Is this drive totally corrupt? I have a LOT of super important data on the main volume that can't get lost—sample libraries that would take hours of work to "relinK" and active vide projects, so I would rather not move everything over to another drive in order to reformat this one. I'm just wondering if this possible corruption is eventually going to have an effect on my main volume.

The drive is a 1 TB SanDisk Extreme SSD.

 

[gilby101]

1) Is you TM destination APFS or HFS+?
2) How did you attempt to delete backups?

With APFS TM destination, the standard way to delete backups is to use the Terminal command: sudo tmutil delete -d /Volumes/<TMDisk> -t 2022-09-02-040133 (or do it in Disk Utility).

If you have any doubts about the state of your backup: get a new disk and start using that.

 

[rm5]

1) Is you TM destination APFS or HFS+?

It's APFS - split into two volumes—one for main data, called "SanDisk 1 TB" and the other for backups, called "Backups"

2) How did you attempt to delete backups?

I was trying to do Cmd + Delete to move to the trash, then Option + Shift + Cmd + Delete to empty the trash, etc.

or do it in Disk Utility

How do you do that?

 

[gilby101]

Disable TM backups whilst doing any of this.

Disk Utility:
In Menus, enable View show all devices, and View show APFS snapshots.
Select your Backups volume - this will be slow whilst it enumerates all the backup snapshots and discovers all the sizes.
If all is well you are able to select snapshots (start with oldest) and click the minus box below. Again this may be slow.

I prefer doing it Terminal.

Deleting in Finder is not a good idea. Hopefully macOS has protected you from corruption - but maybe not!

Even if the Backups has been corrupted, your main boot volumes and the other volume on the external disk should be fine.

To be honest, I don't like messing with my TM volume unless I am confident I have another backup. This could be a second TM backup, or one made with Carbon Copy Cloner (to a different disk), or a backup to the cloud (I use Arq Backup with Backblaze B2 storage).

 

[iLondoner]

Files are not deleted until the trash is emptied, they are merely marked as not to be shown. This is how MacOS is able to restore apparently deleted files. When you dismount an external drive the marker is removed and the file is effectively restored.

The only way to delete files on an external device that you are planning to dismount is to either empty the trash beforehand, or... if you don't want to permanently delete other stuff in the trash, go into the trash and 'delete immediately' on the individual files.

I believe this is the cause of both your issues. Come back again after doing this, and please let us know the problem is sorted.

 

[gilby101]

Files are not deleted until the trash is emptied, they are merely marked as not to be shown. This is how MacOS is able to restore apparently deleted files. When you dismount an external drive the marker is removed and the file is effectively restored.

Trashed files get put in the .Trashes folder on each external drive. This survives a dismount and mount. The files are not restored.

To see the .Trashes folder you will need to use Terminal.

 

[iLondoner]

Trashed files get put in the .Trashes folder on each external drive. This survives a dismount and mount. The files are not restored.

To see the .Trashes folder you will need to use Terminal.

That's not my experience

How to delete files from flash drive on M… - Apple Community

discussions.apple.com

empty trash - Apple Community

discussions.apple.com

https://forums.macrumors.com/threads/troubles-with-my-sandisk-cruzer-usb-drive.114502/

@rm5: best you can do is to try my suggestion. Please report back.

 

[gilby101]

That's not my experience

How to delete files from flash drive on M… - Apple Community

discussions.apple.com

empty trash - Apple Community

discussions.apple.com

https://forums.macrumors.com/threads/troubles-with-my-sandisk-cruzer-usb-drive.114502/

Those links don't support your contention about how trash works. Just as one example: the macrumors thread includes "Unlike Windows, Mac OS creates a trash folder for every drive. When you move something on that drive to the trash, the file is actually moved to the trash folder. Until you tell the computer to delete trash, those files stay on the drive"

@rm5: best you can do is to try my suggestion. Please report back.

@rm5: Be careful taking advice for someone who does not understand how trash works. And which is likely irrelevant for your issue with TM.

 

[mfram]

It's APFS - split into two volumes—one for main data, called "SanDisk 1 TB" and the other for backups, called "Backups"

I have the same type of drive. SanDisk USB-C SSD external. Formatted APFS with two volumes. One for TM. Keep in mind that with APFS that TM backups are not normal "folders". They are APFS snapshots. The "Trash" isn't relevant because the backups are not part of a normal filesystem. When I open my TM Drive I get a list of Backup snapshots. When I right-click on one of the snapshots I get a "Delete Immediately..." option. I believe that's the best way to delete one of the backups.