What does 'Other' mean in Mac storage?

'Other' is the label macOS historically used (and 'System Data' is the modern name on macOS Sonoma and later) for files it can't cleanly sort into a specific category like Apps, Documents, Photos, or Messages. It's a catch-all bucket, not a single folder or file type.

What's actually inside System Data / Other?

  • Caches - temporary data apps and Safari store to speed up repeat use
  • Log files - diagnostic and crash logs from macOS and installed apps
  • Time Machine local snapshots - hourly backup snapshots kept on your internal drive between full backups
  • App support files - data apps store outside their own bundle, like plugins, extensions, and configuration
  • System files - parts of macOS itself that don't count against the visible 'Apps' category
  • Virtual memory swap files - temporary files macOS uses when RAM is under pressure

Why is System Data taking up so much space?

It grows quietly because none of these are things you directly create or manage - they accumulate as a side effect of normal use. A Mac that's been used for a year or more without cleanup, especially with heavy Time Machine backup activity or many installed apps, commonly shows 20-60GB of System Data.

Is it safe to reduce System Data?

Yes, for the components that are meant to be temporary: caches, logs, and old Time Machine local snapshots are all designed to be cleared and rebuilt automatically. What you shouldn't try to manually delete are core macOS system files - those aren't user-accessible for good reason, and removing them isn't how System Data is meant to shrink.

How do I reduce System Data / Other storage?

  1. Clear browser and system caches - see our guide on clearing cache on Mac
  2. Check Storage Management for large Time Machine local snapshots and thin them
  3. Uninstall apps you no longer use, including their support files, with DustByte's App Uninstaller
  4. Review large log files and old downloads with Large & Old Files

Why doesn't emptying Trash reduce System Data?

Trash is tracked separately from System Data in most macOS storage views. Emptying it frees space, but it won't visibly shrink the System Data bar since they're counted as distinct categories - though both contribute to your overall free space.

How much System Data is normal?

A handful of GB right after a fresh macOS install is typical. Anywhere from 10-20GB after months of regular use is common; anything well above that is usually a sign caches or Time Machine snapshots have built up and are worth clearing. For the full picture of reading your storage breakdown, see our complete guide to checking storage on Mac.