Dragging an app from the Applications folder to the Trash removes the binary but leaves caches, preferences, and support folders scattered across ~/Library. Those leftovers add up to gigabytes over time.
Short answer: use AppCleaner (free) to uninstall apps cleanly, or manually remove the matching folders from Application Support, Caches, Preferences, and Logs after deleting the app.
Where leftovers hide
After an app is trashed, its data usually still lives in:
~/Library/Application Support/~/Library/Caches/~/Library/Preferences/~/Library/Logs/
The heaviest one is almost always Application Support — games and creative tools store databases and assets there.
The automated path
- download AppCleaner (free)
- drag the unwanted app from Applications into the AppCleaner window
- review the list of associated files
- click Remove
AppCleaner hashes and matches by bundle identifier, so it finds support files even when folder names do not match the app's display name exactly.
The manual path
If you want to do it by hand after already trashing the app:
- open Finder
- hold Option and click Go > Library
- open Application Support and remove the folder for the uninstalled app
- repeat inside Caches, Preferences, and Logs
Only delete folders tied to apps you are certain you have removed. Wiping Application Support for an active app nukes its saved state.
Better next routes
For deeper cleanup strategies, use the desktop cleanup FAQ.
If you also want the full comparison framing, continue with Best Mac Cleaner App to Free Up Space.