How to free up space on a Mac

Apple's tools first

System Settings → General → Storage has a Recommendations list worth reading before anything else:

• Store in iCloud keeps Desktop, Documents and full-size photos in iCloud and only recent ones on the Mac.
• Optimise Storage removes films and TV programmes you have already watched in the TV app.
• Empty Trash Automatically deletes items that have been in the Trash for 30 days.

Below the recommendations, each category opens a list you can sort by size. What it will not show you is most of System Data, which is where the rest of this page goes looking.

The places Storage settings leaves out

Caches and logs

~/Library/Caches, the hidden ~/.cache, and ~/Library/Logs. All of it regenerates; the cost is apps being slower the first time they open afterwards. How to clear the cache on a Mac has the commands.

Developer files

If you have ever installed Xcode, this is likely the biggest section of the page. On the Mac this app was built on, DerivedData alone was 9.06 GB, and the Android emulator and NDK came to 15 GB when they were removed on 5 September 2026. Old simulator runtimes are several gigabytes each. Package caches for npm, Yarn, CocoaPods, Gradle and Homebrew are re-downloaded on the next install.

AI tool data

Coding agents and AI desktop apps download runtimes and updates and leave build folders behind, almost none of it where Finder shows you. The biggest single item ever reclaimed on that same Mac was here: 9.1 GB of abandoned build trees from earlier coding-agent sessions. The folders to check are listed in the hidden data AI tools leave.

Apps you no longer open

Applications sorted by size, with the date each was last opened, is a better guide than memory. Removing an app through its own uninstaller, or with its support folder, gets back more than dragging it to the Trash.

Duplicates, large files and Downloads

Downloads collects installers you ran once. Duplicate files are worth finding by content rather than by name, so a renamed copy still counts and a different file with the same name does not. These are yours, so look before deleting, or move them to an external drive.

iPhone backups and message attachments

Local device backups can be tens of gigabytes. Delete one only when the device also backs up to iCloud or a newer backup exists. Message attachments can go too, but the conversations keep a blank where each one was.

What to leave alone

The Photos library (use Photos' own settings), Application Support (for many apps it is the data), and anything under /System. If the disk is critically full right now, the shorter triage in Mac storage full is the better place to start.

Where the app comes in

RefreshYourMac measures 45 categories across all of these sections in one scan, rates each one for what removing it would cost you, and shows the result before it deletes anything. The scan is free; see how it decides what is safe.