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Time Machine did not finish backing up because some files were unavailable. Backups will resume when your Mac is unlocked.

I've had no trouble with Time Machine until updating my Mac Mini M2 to OS 15.0.1. After the update, I constantly get the message "Time Machine did not finish backing up because some files were unavailable. Backups will resume when your Mac is unlocked." The backups seem to run fine until reaching about 80% then stall before the message appears. I've tried different ports, different USB C hubs, different cables etc. with the same result. I've scann the resources here and found nothing current or helpful on this issue.

Mac mini (M2, 2023)

Posted on Oct 25, 2024 5:25 AM

Top-ranking reply

Kerry Kinkade Author

Level 1

35 points

Posted on Oct 25, 2024 2:50 PM

After my initial post, I tried erasing my backup drive and starting over with a new time machine backup, but I still got the same message.

After exhausting everything I could think of, I called Apple Care. I spoke with a representative who let me explain everything I had already tried and he indicated that I had covered most of his solutions matrix, so we didn't waste time going over that again (GREATLY APPRECIATED!). I was put on hold for a short time by the rep then asked to do the following:

Eject my backup drive and disconnect it from my Mac;
Open time machine and tell it to forget my backup drive;
Restart my Mac in Safe mode;
Reconnect my backup drive;
Open time machine and tell it to use my backup drive for a new backup;
Let time machine format the backup drive and complete an initial backup to my backup drive;
Confirm the initial backup finished without errors;
Restart my Mac in normal (not safe) mode.

I completed the above steps in pretty short order and have since had 5 hourly backups with no errors. This seems to have solved the problem.

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49 replies

dbrewood

Level 1

96 points

Nov 2, 2024 4:33 AM in response to mjmarch

Well, I tried it all again this time with the firewall off. And as you can see it didn't make a ****** bit of a difference.

I can see that I'll have to raise it as a bug with Apple......

mjmarch

Level 1

45 points

Oct 28, 2024 1:48 PM in response to dbrewood

In either case, you need to erase the previous backups. Must start fresh.

dbrewood

Level 1

96 points

Nov 1, 2024 8:25 AM in response to mjmarch

I'm running 15.1 here and still have the issue. Unless you mean the forthcoming 15.2 update?

Nov 2, 2024 12:46 PM in response to mjmarch

Where do you turn off the firewall? Running Sequoia 15.1

dbrewood

Level 1

96 points

Nov 16, 2024 6:28 AM in response to mjmarch

Have you tried the Spotlight reindex fix I suggested?

You'll lose nothing and it’s now worked for myself, my wife and a friend.

Nov 18, 2024 3:09 PM in response to Kerry Kinkade

This did not work for me.

Nov 18, 2024 3:10 PM in response to dbrewood

Temporally I would predict. Please tell me this was a permanent fix please.

dbrewood

Level 1

96 points

Nov 19, 2024 2:26 AM in response to AceyPilot

Which one, the reformatting of the TM drives or the reinitialisation of Spotlight indexing?

Nov 19, 2024 3:17 AM in response to envoy510

This is interesting. No Spotlight and you have TM issues. Just a shot in the dark, but have you tried reindexing anyway?

Nov 19, 2024 3:45 AM in response to Kerry Kinkade

沒錯我剛剛也是閃爍很久不過是i4

dbrewood

Level 1

96 points

Nov 21, 2024 7:54 AM in response to Kerry Kinkade

After I updated to 15.1.1 that is when the backups broke again.

jarjar2

Level 1

20 points

Nov 21, 2024 12:27 PM in response to AceyPilot

I did and unfortunately this problem just started for me with this update. M1 Mac Studio

mjmarch

Level 1

45 points

Oct 25, 2024 4:18 PM in response to Kerry Kinkade

This procedure worked fine.

I also tried another one with my NAS: I rebooted the Server and the Mac and requested another back-up. For a while the error message for failed backups persisted but when opening the TM Settings, I noticed that the NAS disk showed the time of a backup without a warning attached to it. After the second or third backup to the server, no failed backup messages showed up. It seems that it is all is well now.

mjmarch

Level 1

45 points

Nov 1, 2024 8:47 AM in response to dbrewood

You still have the Router firewall (most come with protection software, including a Firewall).

The TM back up will complete normally if you turn of the Mac OS firewall. Otherwise, you will continue to have issues.

mjmarch

Level 1

45 points

Nov 1, 2024 8:45 AM in response to dbrewood

I meant 15.1 which is out for doing the upgrade. So, I am going to wait and see if 15.2 has the fix. I am getting tired of these constant upgrades which change settings behind my back and clearly are not sufficiently tested. Having back up issues with the firewall is not a minor inconvenience. Bad Apple.

Time Machine did not finish backing up because some files were unavailable. Backups will resume when your Mac is unlocked.