How to free up space on your Mac, step by step

1. See where the space went

Open System Settings › General › Storage for the overview. For a precise picture of your home folder, run this in Terminal. It lists the 15 biggest folders:

du -h -d 1 ~ | sort -h | tail -15

If a huge slice is called “System Data”, read what it really contains.

2. Empty the Trash

Files in the Trash still take space. Empty it, then check your free space again. If nothing changes, here is why.

3. Find big forgotten files

In Finder, press ⌘F, add a filter on File Size and look for items over 1 GB. Old screen recordings, disk images and exported videos are the usual suspects.

4. Clean Downloads and old installers

.dmg and .pkg files are only needed once. Once the app is installed, the installer can go.

5. Uninstall apps you no longer use

Dragging an app to the Trash leaves its data behind in ~/Library/Application Support and other folders. Games and creative tools can leave tens of gigabytes. Remove the app and its leftovers together.

6. Clear caches, carefully

Caches in ~/Library/Caches are rebuilt automatically. Clear the contents of an app’s cache folder, not the folder itself, and not the system caches in /Library or /System.

7. Remove old iPhone and iPad backups

Each backup can weigh tens of gigabytes. In Finder, select your iPhone in the sidebar, click Manage Backups, and delete the ones you no longer need. Keep the latest.

8. Let iCloud help

Turn on Optimize Mac Storage for iCloud Drive and Photos so older files stay in the cloud and download when you open them. This frees space without deleting anything.

9. Deal with duplicate and similar photos

Burst shots and edits pile up. Keep the best of each group and remove the rest.

10. If you code: clean developer leftovers

Xcode, simulators, node_modules, Docker and AI models are often the biggest items on a developer’s Mac. See the developer cleanup guide.

What not to delete

• Anything inside /System or /Library that you don’t recognize.
• Your Mail, Messages and Photos libraries, unless you are sure what you are doing.
• Files in ~/Library/Application Support for apps you still use: that is your data.

Undig Cleaner automates these steps: it explains each item, marks it Safe or Review, and moves it to the Trash with a Journal so you can undo it. It also shows the real size of APFS clones, so you know what you will actually recover.