how do you delete time machine snapshots (i.e backups) on an external disk, NOT local snapshots

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Level 1

42 points

how do you delete time machine snapshots (i.e backups) on an external disk, NOT local snapshots

I use TM to backup my Mini to an APFS volume on an external disk. Using TM I can see my backups/snapshots going back for several years. The Time Machine Mechanic (T2M2) program, which parses the Mini's log files for TM messages, tells me the volume has 132 snapshots. The disk is almost 90% full.

I'd like to delete some snapshots, oldest first. First, I turned off TM. When I choose the volume in Disk Utility and view snapshots, I get a "loading" indicator and a spinner. I let it spin for hours before deciding it wasn't going to work. I ran First Aid on the volume and no errors were reported, but I still can't view the snapshots.

How can I view/delete old TM snapshots on an external disk/volume?

Mac mini, macOS 14.5

Posted on Jul 26, 2024 5:42 PM

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Answer 1

Owl-53

Level 10

105,325 points

Jul 27, 2024 5:31 AM in response to John Kelso

John Kelso wrote:

I use TM to backup my Mini to an APFS volume on an external disk. Using TM I can see my backups/snapshots going back for several years. The Time Machine Mechanic (T2M2) program, which parses the Mini's log files for TM messages, tells me the volume has 132 snapshots. The disk is almost 90% full.

I'd like to delete some snapshots, oldest first. First, I turned off TM. When I choose the volume in Disk Utility and view snapshots, I get a "loading" indicator and a spinner. I let it spin for hours before deciding it wasn't going to work. I ran First Aid on the volume and no errors were reported, but I still can't view the snapshots.

How can I view/delete old TM snapshots on an external disk/volume?

Reformat the Entire Physical Drive

This will remove the Older Snapshots and everything else

Time Machine Backup marks the Drive and Read Only

Therefore, attempting to cherry pick some SnapShots is virtually impossible

The only Software that can both Read and Write to this drive is TM Backup

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Answer 2

Jul 27, 2024 4:59 AM in response to John Kelso

There should be no need for you to manually delete backups. If Time Machine finds that it does not have sufficient room to complete a backup, it will automatically start deleting the oldest back up first and continue until it has sufficient space to complete the desired backup.

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Answer 3

John Kelso Author

Level 1

42 points

Jul 27, 2024 5:51 AM in response to woodmeister50

I've read that. I guess it's sort of a "trust us" design and I hope it works. But I'm not sure.

When I run T2M2 (looking at the last 2 hours) it reports these entries from the TimeMachine logs:

Created 2 new backups

Thinned:

Thinning 1 backups using age-based thinning, expected free space: 919.14 GB actual free space: 919.21 GB trigger 50 GB thin 83.33 GB dates: (

"2024-07-26-071131"

)

Thinning 1 backups using age-based thinning, expected free space: 918.89 GB actual free space: 918.97 GB trigger 50 GB thin 83.33 GB dates: (

"2024-07-26-081508"

)

Created 4 new snapshots, and deleted 4 old snapshots.

and further down it reports this:

2024-07-27 07:28:02.028365-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-01-01-130321.previous

2024-07-27 07:28:02.749197-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-01-29-070932.previous

2024-07-27 07:28:03.011544-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-02-01-093106.previous

2024-07-27 07:28:03.356289-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-02-04-090429.previous

2024-07-27 08:30:31.396442-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-01-01-130321.previous

2024-07-27 08:30:32.184609-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-01-29-070932.previous

2024-07-27 08:30:32.421749-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-02-01-093106.previous

2024-07-27 08:30:32.802930-0400 Error: Error Domain=NSOSStatusErrorDomain Code=-5000 "afpAccessDenied: Insufficient access privileges for operation " deleting backup: /Volumes/hotplate TimeMachine/2023-02-04-090429.previous

Might this explain why the number of snapshots keeps increasing?

Many thanks for assisting with this.

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Answer 4

John Kelso Author

Level 1

42 points

Jul 27, 2024 5:56 AM in response to Owl-53

Is TM's snapshot thinning algorithm documented anywhere? Not just age based, but disk space based.

I really hope it thins the backups. See other comment about error entries in the the TM logs. I guess I'll just wait and see if it becomes a problem before I worry about it.

Thanks for your help!

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Answer 5

den.thed

Level 10

93,346 points

Jul 27, 2024 6:54 AM in response to John Kelso

Trying to manage Time Machine with third party software like T2M2 is worrisome. I say that because any wrong doing manually or by third party software, will bork the backups which will force you to erase everything and start over.

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Answer 6

John Kelso Author

Level 1

42 points

Jul 27, 2024 7:04 AM in response to BDAqua

My backups appear to be working fine. Hopefully this is the case. I can see files stored in recent snapshots.

It's more that I fear my older snapshots aren't getting thinned by TM (based on the errors in the TM log; note the dates of the files generating the errors- the seem to be from about six months ago) and therefore perhaps I will run out of disk space.

It's an APFS formatted WD 12T external disk directly connected to the Mini via USB.

Thanks!

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Answer 7

Owl-53

Level 10

105,325 points

Jul 27, 2024 7:12 AM in response to John Kelso

To truly protect your non replaceable Data - have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive

https://bombich.com

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Answer 8

John Kelso Author

Level 1

42 points

Jul 27, 2024 7:22 AM in response to Owl-53

Yes, I do exactly this, using TM both and CCC, so I don't fear losing any important data. But it doesn't really address my question of increasing number of snapshots.

It would be nice if I didn't have to reformat the hourly TM disk and start over. Yeah, I know, it's really a "first world problem".

Thanks,

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Answer 9

Owl-53

Level 10

105,325 points

Jul 27, 2024 7:48 AM in response to John Kelso

User wrote " I use TM to backup my Mini to an APFS volume on an external disk "

This implies the Physical Drive is used for more than 1 purpose - this that correct ?

Writer ( PRP_53 ) wrote >> Each of the above should be done to a Dedicated Single Purposed External Drive

That implicitly means Not Multi Purposed

When and if the External Drive fails and that do

The user is left with Scrambled Eggs meaning No backups and nothing - gone

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Answer 10

John Kelso Author

Level 1

42 points

Jul 27, 2024 8:05 AM in response to Owl-53

Yes, the external disk has a single APFS container with two volumes. One of these is for the Mini's TM backup, and the other volume is for my laptop's networked TM backup.

Everything seems to be going great except for these permission errors, which of course may be a symptom of impending scrambled eggs.

Is there an Apple TM document which states that an external drive for TM should be dedicated solely to a single TM backup? This should be in red blinking Comic sans letters when setting up a TM backup! It also seems like a pretty dreadful feature of the APFS file system. But then, we work with the file system we have, not the filesystem we want.

Many thanks, I learn something new every day!

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Answer 11

John Kelso Author

Level 1

42 points

Jul 27, 2024 8:32 AM in response to BDAqua

Yes. Isn't SMB pretty much the only game in town now? Anyway, yes, the hourly networked backups to the Mini seem to be working fine, as far as I can tell. I guess I should run T2M2 on the laptop's logs too, now that I think of it.

I'm a big fan of CCC. I wish they could get an easily networked backup solution working.

Thanks,

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