Time Machine backups stalling on MacBook Air M3

My machine is a 2024 MacBook Air M3 chip, MacOS Tahoe 26.6.2.

My Time Machine backups are stalling indefinitely. The current one has been stuck on 24% for the past four days. This wasn't happening a month ago. My hypothesis is that Time Machine is failing to delete the oldest backups, so there is insufficient space on my external hard drive for a new backup. Another thing that seems strange to me is that--if I'm reading it correctly--it seems be backing up approximately 485GB (118.5GB copied and only at 24.4%), but my hard drive only has 236GB in use.

Any help would be very much appreciated!

Posted on Oct 15, 2026 1:27 PM

1 reply

6x6

Level 7 (26,777 points)

Oct 15, 2026 5:51 PM in response to Gr8ful4u

At some point Time Machine can no longer purge older backups. To confirm that your drive is full, open Finder, right-click your drive and choose Get Info.

If your backup drive is full, you have two options. Reformat the drive and start new backups from scratch but you loose your previous backups. The better option is to acquire a new drive and start new backups with it. You then keep your previous drive in case you need to recover older data.