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562 preference files came to 21 MB. Deleting them frees nothing and resets everything

~/Library/Preferences appears in cleanup advice, but it is settings, not storage. Measured at 21 MB, with no file over 1 MB. What deleting them actually does.

3 min read

Old Mac cleanup guides list "remove unused preference files" as a step. It sounds thorough. On a current Mac it is close to meaningless for storage, and it has a real cost.

What these files are

Each .plist file holds one app's settings: window positions, your choices in its settings window, recent files. They are small because settings are small. Even a Mac with a thousand of them would be counting in tens of megabytes.

ls ~/Library/Preferences | wc -l
du -sh ~/Library/Preferences
find ~/Library/Preferences -name '*.plist' -size +1M 2>/dev/null

What deleting them does

  • Resets the app to its first-run state. Settings, licences stored in preferences and customisations go.
  • May not even take effect, because macOS caches preferences in memory through a background process. Deleting a plist while the app runs can have the file rewritten from that cache.
  • Frees almost nothing. 21 MB on this Mac.

When deleting one does help

Removing a single app's preference file is a genuine troubleshooting step when that app misbehaves, with the app quit. That is about fixing the app, not about space. For preferences of apps you have already deleted, they are harmless leftovers; removing them is tidiness, as in what uninstalling leaves behind.

The folders that do hold gigabytes in your Library are in Library Caches and Application Support. Similar advice that sounds useful and is not is collected in Mac storage myths.

Common questions

Is it safe to delete files in ~/Library/Preferences?

It will not break macOS, but it resets each app to its first-run settings. It frees very little: 21 MB in total on the Mac measured.

How big is the Preferences folder on a Mac?

Usually tens of megabytes. The Mac measured had 562 items and 21 MB, none over 1 MB.

Will deleting plist files speed up my Mac?

No. They are small settings files. Deleting one only helps if that specific app is misbehaving.

Why does a deleted plist come back?

macOS caches preferences in memory and rewrites the file if the app is still running. Quit the app before removing it.

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