Can I delete the whole System Data category?

No. macOS manages this changing category; it is not a folder with a safe Delete button. Review separate storage categories and only files whose source and purpose you can identify.

What does tmutil listlocalsnapshots / do?

It lists local Time Machine snapshots on the startup volume. It is an inspection command only and does not delete or modify a snapshot.

Why does the System Data total change by itself?

Caches, logs, staged updates, and local snapshots grow and shrink as macOS and apps work. The Storage view can also take time to recalculate after files change.

How to Clear System Data on a Mac (And What macOS Handles Itself)

Published 2026-09-09 · Star Cleaner

What is inside System Data on a Mac?

System Data is Apple’s storage label for files that do not fit categories listed elsewhere, not a single folder. It can include log files, caches, VM files and other runtime system resources, temporary files, fonts, app support files, and plug-ins.

Local APFS Time Machine snapshots can also contribute. You cannot manage the contents of System Data directly; macOS manages them.

Should you delete local Time Machine snapshots?

Usually, no. Snapshot space is already counted as available storage, and macOS deletes snapshots automatically when their space is needed. No manual action is normally required for snapshot space.

For inspection, open Terminal and run tmutil listlocalsnapshots /. This is a safe, read-only command that lists local snapshots; it changes nothing. Do not treat the list as an instruction to force-delete snapshots.

What can you review separately from System Data?

1.In the separate iOS Files storage category, review old iPhone and iPad backups through Finder: connect the device, select it, then choose Manage Backups. Remove only backups for devices or dates you no longer need.
2.Mail is also a separate storage category. Remove downloaded attachments through Mail, and clear app downloads or caches through the app that created them. This preserves the app’s own bookkeeping.
3.Use Xcode or the relevant developer tool to remove obsolete simulators, archives, and build products rather than deleting unfamiliar Library folders by hand.
4.Finish pending macOS updates and restart before checking Storage again. Staged update files are managed by macOS and can change after the update completes.

Why does Star Cleaner leave System Data alone?

Star Cleaner does not clear System Data on a Mac. Its Mac tools work on user files: the photo library, large files, exact duplicates, similar photos, and a disk breakdown. System paths are hard-protected, and nothing is deleted until you review and confirm it.

Frequently asked questions

Can I delete the whole System Data category?: No. macOS manages this changing category; it is not a folder with a safe Delete button. Review separate storage categories and only files whose source and purpose you can identify.
What does tmutil listlocalsnapshots / do?: It lists local Time Machine snapshots on the startup volume. It is an inspection command only and does not delete or modify a snapshot.
Why does the System Data total change by itself?: Caches, logs, staged updates, and local snapshots grow and shrink as macOS and apps work. The Storage view can also take time to recalculate after files change.