My Time Machine backups have started to take longer and longer to process and complete. I realized that excluding folders containing temporary, frequently changing and large files would quite dramatically speed it up.

Here's what I excluded from System Preferences > Time Machine > Options...:

Time Machine Options Exclusions

  • Safari, Vivaldi and Chrome browser caches:
    ~/Library/Application Support/Vivaldi/Default
    ~/Library/Application Support/Google Chrome
  • Xcode and developer libraries:
  • And any other folders you don't mind losing. In my case, I added my Downloads and VM folders too.

The Vivaldi and Google folders above may also contain bookmarks and other files, so it's best to be a bit more fine grained than I am, but this is good enough for me since I think they are stored in the Cloud in any case.

One could go all the way and exclude all /Applications and ~/Library/Caches on the assumption that these could be re-downloaded or re-generated as needed anyway. And even exclude the ~/.Trash...

If you have trouble finding these folders, either:

  • Press Command + Shift + G and type them in e.g. ~/Library,
  • Or, search and press the + button to add System files are included to the search filter.