> Time Machine grinds to a halt
After updating Adobe Photoshop Lightroom, routine Time Machine backups have ground to a halt and just run on forever. Should I upgrade from Catalina, or is there something simpler that can solve this issue?
Each major new version of macOS has brought substantial changes to Time Machine’s backups, and although they seem to have worked out quite well in early releases of Catalina, they’ve become steadily less reliable and more likely to choke on certain folders.
The most likely to cause backups to grind to a halt is the hidden versions database on your Data volume, which often slows the rate at which files are copied to your backup from 50MB/s or more to less than 0.1MB/s. This can also occur with other folders containing very large numbers of smaller files, or many hard links.
If your Lightroom files contain a folder named Previews with tens of thousands of files, that could be responsible. You can check this using the free utility T2M2 from bit.ly/ mac361t2m2. If that’s the case, adding that folder to Time Machine’s list of exclusions could solve your problem.
In the longer run, you should upgrade to Big Sur, which has improved backups made to APFS volumes, as well as supporting the older format on HFS+. The latter excludes the versions database, and may not choke as easily on folders containing many files either. But most Time Machine users are switching to backing up to APFS, which is more reliable.