greyspace · Guides
System Data, explained
Step-by-step guides to the things that fill the grey System Data bar, with the manual steps that work without greyspace.
What is System Data on a Mac, and why is it so big?
System Data in Mac storage explained: what the grey bar contains (app data, startup and recovery volumes, system files, caches, swap, Spotlight, snapshots, backups), why it can grow to 100 or 200 GB, and how to check each part safely.
Read the guideWhy is my Spotlight index so big, and how do I rebuild it?
How to check the size of the Spotlight index on a Mac, why it can grow huge and land in System Data, and how to rebuild it safely from System Settings or with mdutil.
Read the guideHow to delete Time Machine local snapshots on a Mac
Time Machine local snapshots can fill System Data. How to list them with tmutil, delete one or all of them safely, use Disk Utility instead, and what happens to your backups.
Read the guideHow to remove aerial screen saver and wallpaper videos on a Mac
The moving aerial wallpapers and screen savers on macOS are downloaded videos that count as System Data. Where they're stored and how to remove the ones you don't use.
Read the guideHow much storage does Apple Intelligence use, and how do you get it back?
Apple Intelligence downloads its models to your Mac, where they count as System Data. Where they're stored, why you can't delete them by hand, and the setting that gets the space back.
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