Time Machine backup on macOS Sequoia cannot be completed

Exactly the same for me. Never an issue until Sequoia 15.0 and no resolution with 15.1 or 15.2 updates.

Backups work fine as long as the machine is awake. However, once it goes to sleep, upon waking you see the attached error message. My external drive is named "Time Machine" so it appears redundant, but in short the Time Machine software could not backup to the Time Machine drive.

Once the machine is awake and unlocked, all backup functionality returns to normal.

I found a 3rd party utility that helps with analyzing the Time Machine backup logs and used it extensively to try and figure out what was going wrong. No success, so I am at the mercy of Apple to figure out where Time Machine went off track with the release of Sequoia.

My macbook air has succeed at TimeMachine backups.

Moreover, the result of `mutil listbackups` showed even backup lists.

Coincidentally, the power cable was disconnected just as the backup was successfully completed.

After that, backups were consistently successful when the power cable was connected.

If someone continue to fail TimeMachine backup, try to run with battery.

Not a solution, but a small detail that might aid in your thinking about this issue. I have the same issue with my MacBook Pro (13" M1 2020 to Seagate 2TB) since OS15 was installed: Time Machine will not complete after having been active for many minutes. I perform backup on all my computers the first day of every month. The first instance of this disruption was 12/1/24.

Unexplainedly, Time Machine DOES complete with my MacAir (M1 2020) which is also running OS15.

In trying to run the error message to ground on my MacBook Pro, SPOTLIGHT won't take me to the source of the problem that Time Machine identifies. So I poke around looking for the file. Maybe if I can find the file and delete it, Time Machine will complete. OTOH this may be just the first file of a never-ending list of files that really have nothing to do with the real as-yet unidentified problem!

Upgrading to macOS 15.3 seems to have finally fixed my problem of Time Machine not backing up to my NAS drive when my computer was hibernating.

When I first upgraded to 15.3, the problem continued. But then I removed my NAS drive from Time Machine settings, rebooted, then re-added the drive. I have gone ~ 10 days and have not encountered a single backup failure when my computer was unattended. (I tried this sequence under v15.0, 15.1.x, 15.2.x but it did not solve my problems then.)

So I am assuming that Apple fixed the bug in 15.3.

I never experienced some of the issue discussed in this thread, namely file access; just failure to backup when the computer was unattended.

Hey Everyone,

You most probably have already been told by Apple support that Time Machine through Time Capsule is considered "obsolete technology" and is no longer supported. If you are running Sequoia you can't backup wirelessly or ethernet any more. A possible workaround is to connect a SSD via USB to backup up.

This "obsolete technology" thing really ticks me off, in just a few months Apple managed to kill off all my intel powerhouses MP and MBP and now time capsule.

I noticed this time that I removed the NAS drive, bootstrapped, then re-added it, there was a new prompt checking on the drive which I had not seen before. Perhaps it will work this time under 15.3. One can hope.

After being on 15.3 for a bit, my issue has resolved. When I wake my machine there is not longer the error on incomplete backup, so all good. Don't know what Apple changed, but thanks.

I have nothing but issues with Time Machine since upgrading to MacOS 15.0 - was hoping it would be resolved under 15.0.1. Removing and re-adding the two APFS drives I have attached sometimes resolves the issues but eventually the error continues.

Time machine occasionally fails to complete its backup operations due to files unavailable error. Interestingly, it completes once I am active on the MBP M1 16" running 15.0.1. Not sure what I can do next to avoid the issue.

From completely formatting my previous backup drive did not solve the Time Machine failure to back for me.

I given up. I purchased a 3rd party option for backups. Not the same as TM, yet better than not having anything!

Unfortunately the terminal command didn't work for me. I've tried turning off Firewall as was implied. I have Removed the drives within the TimeMachine setting and re-added, I have run Disk FirstAid on both. I also run Netgear's Armor and though perhaps the TimeMachine protection within that app was the problem, but turning off hasn't resolved. I guess my next step is to start from scratch with my two APFS disks but that defeats the purpose of having a back up that I can go back months and even years to recover something I don't currently know I might be missing.

My Time Machine backs up fine until my iMac goes to sleep. Upon waking, I see the error message that it could not complete the backup. Then it backs up fine. More of an annoyance for me than anything, but something I hope Apple fixes. 24" M1 2021 running MacOS 15.0.1

I have the same problem, I removed the WDMyCloud drive from the Time Machine prefs, but, when re-adding it, the "Checking Capabilities of Time Machine backup drive" just hangs forever. Is there any other option?

I can mount and access the backup drive.

thanks.

I have the same problem. After removing the WD MyCloud Time machine drive, then re-adding it, I also got "checking capabilities of drive..." . Wouldn't add it. It would hang forever. Then I tried connecting with a different MyCloud server. It worked this time. .Was able to re-add the disk to TM.

thanks.