Finding apps you never open, and why the Mac often cannot tell you

The quickest space on most Macs is apps nobody opens. The problem is knowing which ones they are, because the date macOS uses for that lives in Spotlight's index, and the index is not always complete.

The Finder way

1. Open Applications in Finder and switch to List view with Command 2.
2. Right-click the column header and turn on Date Last Opened.
3. Sort by it. The oldest dates are the candidates.

The Terminal way, with sizes

for a in /Applications/*.app; do
  d=$(mdls -raw -name kMDItemLastUsedDate "$a")
  s=$(du -sh "$a" | cut -f1)
  printf '%-26s %6s  %s\n' "${d:0:10}" "$s" "$(basename "$a")"
done | sort

When the dates are blank

A missing date does not mean an app was never used. It means Spotlight has no record, which happens after a migration, after rebuilding the index, or when Spotlight's view of /Applications is stale. Two things help:

• Re-index the apps: mdimport /Applications asks Spotlight to read them again. Dates only start recording from real use after that.
• Use judgement meanwhile: an app you cannot remember opening, and that is not a dependency of something else, is a candidate whatever the date says.

Rebuilding Spotlight is in the Spotlight index guide.

Remove the app and what it left

Dragging an app to the Trash leaves its caches, containers and support files behind, and for some apps those are larger than the app. Delete versus uninstall explains the difference, and the Applications folder guide covers which apps are the heaviest.