Mac storage is full but you can’t find what is using it

When storage looks full but your Documents and Downloads are small, the space is almost always in hidden or system-managed places. Work through these in order.

1. Restart and re-check

The Storage panel calculates in the background and can be stale. Restart, wait a few minutes, then look again.

2. Look at the categories, not the total

Open System Settings → General → Storage and check the largest bar. If it is System Data, see what is in it. If it is Photos, Mail or iCloud Drive, the fix is inside those apps.

3. Check for leftover installers

An Install macOS … app in /Applications is 12 GB or more and can be deleted once the upgrade is done. Large .dmg and .pkg files in Downloads are the same story.

4. Show hidden files

In Finder, press Cmd+Shift+. to toggle hidden items. Then check ~/Library sizes with:

du -sh ~/Library/* 2>/dev/null | sort -rh | head -15

5. Other things people forget

• Time Machine local snapshots
• iPhone and iPad backups
• Other user accounts on the same Mac
• The Photos library (check Recently Deleted)
• Docker and virtual machines

Don’t delete anything you can’t identify. If you want a ranked, explained list first, McCleaner scans these places for free and changes nothing until you choose.

Disclosure: this guide is published by the developer of McCleaner. Scanning is free; cleaning is paid, from €1.99. Back up important data before deleting anything. Commands are provided as is.