Time Machine not working on macOS Tahoe 26.2

macOS Tahoe is absolutely the culprit. It messed up my almost three years of backups. After upgrade to Tahoe, TimeMachine started giving "disk full error" message even though it had consumed all the disk capacity.

Starting backups afresh on a freshly formatted disk did not help. Same error message. In frustration I ended up calling Apple Support. After about a month, of several screen sharing sessions, the following steps are showing promising signs of working again.

The fix at least for me involves starting backups afresh. So you will lose all your older Time Machine backup history.

The fix was to delete some backup related settings via the command line.

The commands to enter in a Terminal shell are:

sudo xattr -d com.apple.timemachine.private.structure.metadata /System/Volumes/Data
sudo xattr -d com.apple.backupd.ModelID /System/Volumes/Data
sudo xattr -d com.apple.backupd.HostUUID /System/Volumes/Data
sudo xattr -d com.apple.backupd.ComputerName /System/Volumes/Data
sudo xattr -d com.apple.backupd.BackupMachineAddress /System/Volumes/Data

After all this if

sudo xattr -l /System/Volumes/Data

returns

purgeable-drecs-fixed:

and nothing else, then in theory that is all you have to clean up before resuming Time Machine backup again.

Your macOS machine may not have all these values defined. So just ignore if the command throws an error or warning. I was too tired to challenge and optimize. I just ran the commands blindly.

After this, I reformatted the Time Machine backup disk and restarted the backup. It has been 24 hours and it has not thrown an error. So I decided to share what I had learned here early.

If I encounter failures again, I will post again. Try these steps and see if it works for you. Hope this helps you recover too. I am feeling somewhat relieved now knowing that I have a good backup again now.

I am thankful to Apple Support to help me recover.

I to have the problem :-( so i choose to get a CCC license and a new SSD Samsung T7 and start from the beginning with Carbon Copy Cloner and it works like a charm :-)

Using Tahoe 26.2 time machine will not back up. sends message “/Users/bobferguson/Library/HTTPStorages/com.microsoft.EdgeUpdater/httpstorages.sqlite-wal” could not be backed up. File HTTPStorage..... does not exist on computer.

My MacBookAir M4 2025 stopped making updates on my Time Capsule after I downloaded Tahoe 26.2. The disc is not available, is the message. How do I go on? My wifes MacBook Air M1 2020 with Sequoia 15.6.1 works fine with Time Capsule. There seems to be a problem with the OS

For me the backup process until 25%.. and always broke after..

macbook pro m1 max, Tahoe 26.2 (25C56)

diskstation DS420+, DSM 7.3.2-86009

I have created a fresh timemachine partition named macbook on the DS, to avoid conflict with the old one.

Same problem here. I backup both my Mac and my MacBook on a Synology NAS. Everything worked fine until 26.2. Now the Mac still works, but my Mac Book doesn't backup.

Time Machine starts the backup, takes hours and then starts over. It doesn't matter whether its over WiFi or Ethernet.

What a mess.

Replying to Khansson - not OP.

I think this is a different problem. Apple Time Capsules are not supported by OS26 and if you've been using a Time Capsule for backups on Sequoia prior to updating then you should have been getting warnings.

https://discussions.apple.com/thread/256113734?sortBy=oldest_first

Wow, this just saved me so much trouble!!! I just couldn't get my Time Machine to work properly. I was backing up a 1TB drive with 300GB of free space to a 2TB Time Machine drive formatted as APFS and it would FILL the disk on the first backup and not even complete it, and then complain that the disk was full and quit.

Running these CLI commands seems to have totally fixed it. First backup was accurate in terms of space taken up, and the subsequent hourly backups are happening without incident.

Thanks for posting this!

The fact that it's working on one of your Macs and not the other suggests a machine-specific issue, or a connectivity issue.

My last TM backup from this Mac running 26.2 to my Synology DS223j took the usual ~5 minutes and finished about 15 minutes ago.

My MacBookAir M4 2025 stopped making updates after I downloaded Tahoe 26.2. The disc is not available, is the message. How do I go on?

when can we expect a fix? I was forced to update to tahoe.. like usual with apple it's just a mess...

I'm near to install linux on my macbook...

don't do that if you haven't a Data volume to install this trojan.. ;)

Tried your solution, It managed to do one backup relatively fast, but then the second one hangs... I hope Apple comes up with a real fix soon.

There have been reports of issues with TM backups to an NAS, though personally my Mac running 26.2 is backing up just fine to my NAS (a Synology DS223j).

One known issue is when the computer name or backup name contains a special character, the backups fail. For example, MacBackup would work but MacBacküp would not, because of the umlaut. Changing the name solves that issue.

When TM 'refuses to make backups' what actually happens? Does the backup start? Get stuck? Is there an error message?