Time Machine Backup Fails After Upgrading to Sequoia

The problem is not with the backup disk, or the files being backed up. As the OP said, and I experienced, Time Machine has been working fine for years, and it quit working after updating to Sequoia.

The answer is not in some Time Machine setup documentation.

Can we just admit that Sequoia broke it and Apple needs to fix it?

Time Machine used to work. It worked for years. Just updated my MBP Intel from OS 14.7 to 15.1 and now Time Machine works until it finds a file it says it can no longer backup and completely fails. If you remove that file, then Time Machine fails on a different file. This process continuous. Hoping someone out there is reading this and fixes this.

As has been said by many: It has not the backup disk. It is not some subtle point in the set-up. Sequoia simple broke TM. I even skipped 15.0 and waited for 15.1 just to avoid this annual "new OS breaks something that's always worked" phenomena. How does Apple test this software?

Got me as well. I've never had a problem with Time Machine on various MacBooks, Mac Mini, and my current Mac Studio...until today. Thanks, Apple, your Sequoia release broke Time Machine backups.

For me it was noted a .mov file from within my User/Library and it was apparently in a message attachment. I tracked down the offending file, moved it to the trash, and Time Machine was able to complete- at least for now. We shall see if anything else causes Time Machine backups to fail.

You’re welcome. Enjoy your Apple gear.

One month in, and I'm guessing there's no solution to this problem? I just reformatted my Backup-disk, expecting TM to get back in gear.... just to find that the only option in the app is to retrieve old backups....

I'm guessing a genius at Apple came up with another great idea to push users towards their overprices iCloud service.... ?

It’s fixed … for me

i had to format the backup disk, then create a new backup, toke like 2 days for around 1gb data…

now it’s working fine, as before the upgrade

I have been struggling with this for the past couple of weeks and have been running 15.X betas. It was failing to snapshot the disk "Untitled" which appears to be the boot partition separate from all of my personal data which is on the "Untitled - Data" partition. I unmounted the "Untitled" partition in Finder and got some errors which I clicked through (we'll see what happens when I reboot). I am now running the backup without the immediate failure. Will update after backup completes and I reboot system.

Time Machine has always do this with every Mac OS upgrade! This is why I think Time Machine isn’t worth it anymore and with third party shareware backups that continue software! I just wait a few weeks for an update to continue backing up!

somethings wrong with Backup now, I had the same issue, so y chose to format the backups disk. now its creating the new backup, but its taking to much time, 22 hours by now at 43%. the previous version create the backup in 9 hrs.

Two days for 1GB of data? That's not right. I have 1TB of data

I don't think the fix for Time Machine should be to discard a year's worth of backups.

I also use Backblaze, but being in the cloud it's slower for restoring large amounts of data, or a whole disk.

Sorry my mistake, I mean 1 TB, I agree to lose my previous backups, (I don't need those) now its working fine, I think they may change some steps on the backups process that fail with the old ones.

I think we may test, if posible, to restore from the "damage backup" and the new ones from 0, like mine.

Previously TM failed stating that it was "unable to backup" a file. That file was more than two years old. Seemed to have nothing to do with that file in particular.

I reformatted my external SSD that I use for TM to APFS without encryption and case insensitive (not 100% sure it was APFS previously). While I lost all my old backups from over the last year, I was able to do a full image and two daily backups over the last three days.

The only quirk now is that even though I have selected backup every hour, TM does not backup unless I manually tell it to do so. At least now it is backing up.

Perhaps some remedy is listed here. At worst, the last bullet should be effective.

If you can't back up or restore your Mac using Time Machine - Apple Support

It's literally the worst. No matter WHAT you do, it will never work. It's broken.