Mac "Other" Storage Is Full — Here's What It Actually Is and How to Clear It

Open About This Mac → Storage and there it is: a huge gray bar called Other (or "System Data" on newer macOS), often 50 GB or more. Apple never explains what is inside it. Here is what it actually contains — and what is safe to delete.

What counts as "Other"?

Anything that isn't a photo, video, audio file or app binary lands in Other:

• App caches — browsers, chat apps and design tools cache aggressively
• Old installers — .dmg and .pkg files forgotten in Downloads
• Developer junk — Xcode DerivedData, iOS device support files, old simulators
• App leftovers — support files from apps you deleted long ago
• Logs and diagnostics — crash reports and system logs
• Time Machine local snapshots — kept when your backup disk is unplugged

Safe to delete right now

1. ~/Library/Caches — apps rebuild caches automatically. Sort by size, delete the biggest offenders.
2. ~/Downloads — search for .dmg and .pkg; installers are useless after installation.
3. ~/Library/Developer/Xcode/DerivedData — safe for developers to clear entirely; Xcode rebuilds it.
4. Leftovers of deleted apps in ~/Library/Application Support — folders named after apps you no longer have.

Never delete inside /System or /Library/Extensions — those belong to macOS itself.

The one-click way

SuperCleanerPro's Smart Scan finds all of the above in a single pass — caches, installer packages, Xcode junk and orphaned app files — shows exactly how much each category holds, and lets you review before cleaning. Most Macs reclaim 10–40 GB on the first run.