Previously, I wrote about Time Machine “error 45”, an obscure bug in macOS Catalina. I still have no idea what was causing backups to fail, nor what “error 45” means. However, I am happy to report that I think this issue has been fixed in Big Sur.

Time Machine backups failing on macOS Big Sur

I upgraded the same machine experiencing this issue — a 2020 Intel MacBook Pro — to Big Sur a little over a month ago. So far, so good. Time Machine has been working consistently and reliably. No more “error 45” failures.

I hope the error does not return, but if it does, I will update this post.