Tidy MacOn macOS Tahoe, System Data is the same mix as on other versions: Time Machine local snapshots, iPhone and iPad backups, app caches and data, developer and AI files, plus Apple Intelligence models. Restart, thin snapshots, remove old device backups, clear caches of closed apps and clean developer files with their own tools. Leave macOS and Apple Intelligence files alone.
- Restart your Mac.
- Thin Time Machine local snapshots with tmutil.
- Remove old iPhone and iPad backups in Finder › Manage Backups.
- Clear caches of closed apps in ~/Library/Caches.
- Clean developer files and remove unused AI models.
- Turn off Apple Intelligence features you don’t use if you want to stop new models downloading.
What’s in System Data on Tahoe
The same categories as Sequoia and macOS 27: snapshots, device backups, app caches, developer files and local AI models, plus macOS’s own files and Apple Intelligence models, which you can’t remove.
Steps
The steps are the same as on macOS 27; see the full macOS 27 guide for each command. In short:
sudo tmutil thinlocalsnapshots / 999999999999 4
du -sh ~/Library/* 2>/dev/null | sort -h | tail -15
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If System Data is over 100 GB
See System Data over 100 GB for the five usual causes and how to tell which one it is.