What are Time Machine local snapshots? Can you delete them?

Where it is

What it is

When Time Machine is turned on, macOS takes regular APFS snapshots of your startup disk. A snapshot is not a folder you can open. It is a record of the disk at one moment, which lets you restore recent versions of files even when your backup drive is not connected.

A snapshot takes almost no space when it is created. It grows as you change or delete files afterwards, because the old data has to be kept for as long as the snapshot exists. This is why deleting a large file sometimes frees no space straight away.

macOS counts snapshot space as purgeable. It keeps snapshots for roughly 24 hours and deletes them earlier if the disk gets full, so most of the time they look after themselves.

How big it gets

From almost nothing to tens of GB, depending on how much you changed or deleted since the snapshot was taken.

How to shrink it the right way

1. Run the command below to list the snapshots on your startup disk. Each one ends with a date and time stamp.
2. To delete one, run tmutil deletelocalsnapshots followed by that date stamp, for example tmutil deletelocalsnapshots 2026-10-10-093015.
3. Check free space again. It can take a moment for the figure in Finder to update.
4. Do not turn Time Machine off just to avoid snapshots. Your backups to the external drive are what protect you.

tmutil listlocalsnapshots /

What happens afterwards

You can no longer restore files from the moment that snapshot captured. Backups already on your Time Machine drive are not affected, and Time Machine takes new snapshots on its normal schedule.

How Diskzy handles it

Diskzy shows snapshots under System Data marked "Managed by macOS" and does not offer to delete them.

Related guides

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• swapfile/private/var/vm/swapfile0
• iPhone and iPad backups~/Library/Application Support/MobileSync/Backup
• Trash~/.Trash