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I have had no TM problems with Sequoia. I've used both TM and CCC with hard drive and SSD backups.

It just depends on what software you're running and how you are using the computer. It also depends on how observant you are; you simply might not be noticing that overnight TM backups are failing. Have you queried the logs to confirm there have been no errors?

Add the FindMy widget to your desktop. Then ensure that TM backups do run overnight while your computer is locked. I think that's a reliable way to trigger it. As soon as you unlock your computer, look for the error in the Time Machine section of System Settings. If you let a new backup run before you check, you won't be aware that a backup during the night failed.
 
It just depends on what software you're running and how you are using the computer. It also depends on how observant you are; you simply might not be noticing that overnight TM backups are failing. Have you queried the logs to confirm there have been no errors?

Add the FindMy widget to your desktop. Then ensure that TM backups do run overnight while your computer is locked. I think that's a reliable way to trigger it. As soon as you unlock your computer, look for the error in the Time Machine section of System Settings. If you let a new backup run before you check, you won't be aware that a backup during the night failed.
I normally run Time Machine backups manually so haven't run into the problems that are being described here but out of curiosity I decided to try your test. FindMy on the desktop, computer set to sleep and Time Machine backups to run every hour. As near as I can tell, Time Machine ran as expected with no errors displayed in System Settings. Running 15.6.1 on an M1 Studio Ultra.
 
I normally run Time Machine backups manually so haven't run into the problems that are being described here but out of curiosity I decided to try your test. FindMy on the desktop, computer set to sleep and Time Machine backups to run every hour. As near as I can tell, Time Machine ran as expected with no errors displayed in System Settings. Running 15.6.1 on an M1 Studio Ultra.

I appreciate you running that test. When my computer is asleep, backups run less frequently than hourly. But, if you see evidence that the backup was made without error while the computer was asleep, then that's great information.

People who run manually will never have the issue. At the moment the TM backup starts, a disk snapshot is made. Certain files on that snapshot are inaccessible if the snapshot is made while the computer is locked.
 
I appreciate you running that test. When my computer is asleep, backups run less frequently than hourly. But, if you see evidence that the backup was made without error while the computer was asleep, then that's great information.

People who run manually will never have the issue. At the moment the TM backup starts, a disk snapshot is made. Certain files on that snapshot are inaccessible if the snapshot is made while the computer is locked.
My backups didn’t happen every hour overnight as well. Would there be some way for me to check if there were any problem files in the snapshots? There weren’t any errors in Time Machine System Settings.
 
My backups didn’t happen every hour overnight as well. Would there be some way for me to check if there were any problem files in the snapshots? There weren’t any errors in Time Machine System Settings.

Sorry I didn't respond sooner. Assuming the backups you care about ran in the past 8 hours, then in Terminal you can run.

Code:
log show --last 8h --predicate 'process=="backupd"' | grep "Failed to acquire"

You could put any length of time. You'll probably get no output, which means you had no errors. Post #185 shows an example of output having the error.
 
Spoke too soon. Just got the error this morning with 15.6.
Yeah it was fixed for me, but now has resurfaced with 15.6. It seems to only do it when the computer display is asleep (my computer is set to never sleep). I close out the notification (and do nothing else) and subsequent backups are completed without any error.
 
Sorry I didn't respond sooner. Assuming the backups you care about ran in the past 8 hours, then in Terminal you can run.

Code:
log show --last 8h --predicate 'process=="backupd"' | grep "Failed to acquire"

You could put any length of time. You'll probably get no output, which means you had no errors. Post #185 shows an example of output having the error.
Thanks for taking the time to help me with this. I let Time Machine run on Auto overnight and ran your script in Terminal before another backup was made. I don't know what's different between your setup and mine but I didn't get any errors. Thanks again for your help.
 
I decided to remove my Time Machine exclusion just to test the waters. I haven't had any errors over the last few nights. In the past I would always have a problem with the bluetooth-related milod daemon. So, my reliable failure example is failing me. If the problem resurfaces, I'll reintroduce the exclusion.

I believe behavior is the driver for the problem - what software is run and how the computer is used. I haven't intentionally done anything different for the last few nights, but it was mostly over the weekend and I wasn't working with my computer during the day as much. Now that a new work week has started, it will be interesting if the problem comes back.
 
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im having the same problems latest macos , monitor goes to sleep , computer stays on 24/7

when i come back to the computer after a few hours it says time machine not complete or unable to do it

i removed and added the drive again and still no fix
 
I’ve had my TM exclusion removed for over a week now. I’ve not had any backup problem in all that time.
 
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I have been suffering this same bug for some time now. Reviewing the earlier posts here I tried a few things, and the only thing that has worked for me is to exclude ~/Library/Daemon Containers from the TM backup.

I am running a Mac mini M2 on Sequoia 15.6.1 (24G90) with a studio display attached. The display goes to sleep after 3 hours and locks the Mac when it does. Until I made this exclusion for the TM backup, I would get the Time Machine unable to access files error message every time I unlocked it. Now I don't get the error any more. I have never had the FindMy widget installed on this mac.

In the folder ~/Library/Daemon Containers I have 13 subfolders dating from last night to March 2023, ranging from 3KB size to 91.4 MB size. Are these folders important? Should I delete them / keep them? Will a restore from TM work if these folders have been excluded from the backup?

I have no idea how important it is to have the folder ~/Library/Daemon Containers in the TM backup in order to be able to restore my Mac in an emergency. And advice and thoughts from this community?

Many thanks
 
In the folder ~/Library/Daemon Containers I have 13 subfolders dating from last night to March 2023, ranging from 3KB size to 91.4 MB size. Are these folders important? Should I delete them / keep them?
I looked at mine; I have 12. Each of these seems to contain a hidden file .com.apple.containermanagerd.metadata. If you look in that file at the line after <key>MCMMetadataCreator</key> you'll see what looks like an Apple daemon process or subsystem name. Some might give you a clue as to what they're for:

com.apple.syncdefaultsd
com.apple.privatecloudcomputed
com.apple.intelligentroutingd
com.apple.linkd
com.apple.StocksKitService
com.apple.businessservicesd

I would advise against deleting anything in ~/Library/Daemon Containers !

Will a restore from TM work if these folders have been excluded from the backup?
I *think* the answer is yes. Before a whole-system restore, you would first do a fresh install of macOS (usually from Recovery mode). So right there you have a working system. If you don't restore these Daemon Container files, I suspect the system will continue to work, even after using Migration Assistant to restore your user files/system settings/personal settings/apps from the backup.

However, I haven't tried it. To be sure about it, you should try it, perhaps with a spare external drive.
 
I have been suffering this same bug for some time now. Reviewing the earlier posts here I tried a few things, and the only thing that has worked for me is to exclude ~/Library/Daemon Containers from the TM backup.

I am running a Mac mini M2 on Sequoia 15.6.1 (24G90) with a studio display attached. The display goes to sleep after 3 hours and locks the Mac when it does. Until I made this exclusion for the TM backup, I would get the Time Machine unable to access files error message every time I unlocked it. Now I don't get the error any more. I have never had the FindMy widget installed on this mac.

In the folder ~/Library/Daemon Containers I have 13 subfolders dating from last night to March 2023, ranging from 3KB size to 91.4 MB size. Are these folders important? Should I delete them / keep them? Will a restore from TM work if these folders have been excluded from the backup?

I have no idea how important it is to have the folder ~/Library/Daemon Containers in the TM backup in order to be able to restore my Mac in an emergency. And advice and thoughts from this community?

Many thanks

I would second @Brian33's response.

I suspect it's safe to have excluded these folders from the backup and still have a successful restore.

I also have 13 folders under there. In the past I only had to exclude a single one to have TM work properly. But, I have no exclusions now, and haven't had any for almost 2 months, and don't have any TM issues. That suggests that you should, now and again, remove your exclusions to retest and see if they're needed any longer. Perhaps do that after each update from Apple.
 
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