TidyMacTime Machine local snapshots are hourly restore points stored on your Mac’s internal drive. They’re safe to thin: your backups on an external or network drive are not touched. List them with tmutil listlocalsnapshots / and thin them with sudo tmutil thinlocalsnapshots / 999999999999 4.
The five questions
Restore points Time Machine keeps on your Mac's own drive, roughly every hour, so you can get back recent files even without your backup drive.
Each restore point holds older versions of files you changed or deleted. macOS is meant to clear them when space runs low, but it doesn't always do it quickly.
Yes. Thinning only removes recent restore points stored on this Mac.
You can't go back to those exact moments from this Mac. Backups on your external drive or network are not touched.
Yes, while Time Machine is on. That's normal; TidyMac keeps an eye on the size.
How big it gets: From nothing to 50 GB or more. They grow fastest when you edit big files (videos, VMs, Xcode projects) and when the disk is already nearly full, because macOS is slow to purge them.
Why "purgeable" space doesn't always come back
macOS counts snapshot space as purgeable, which means the system promises to delete it when an app needs room. In practice that release can lag, so Finder shows plenty of space while installers still fail with "not enough disk space". Thinning the snapshots yourself makes the space real immediately.
Snapshots vs. your actual backups
Local snapshots live on the same drive as your data, so they don't protect you if that drive fails. Your real backups are on the external or network disk you chose in Time Machine settings, and thinning local snapshots leaves those exactly as they are.
Do it yourself
Open Terminal and type: tmutil listlocalsnapshots / to see them. To thin them, type: sudo tmutil thinlocalsnapshots / 999999999999 4 and enter your password.
sudo tmutil thinlocalsnapshots / 999999999999 4
See your own time machine snapshots in seconds
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Frequently asked questions
Is it safe to delete time machine snapshots on a Mac?
Yes. Thinning only removes recent restore points stored on this Mac.
Why are my time machine snapshots so big?
Each restore point holds older versions of files you changed or deleted. macOS is meant to clear them when space runs low, but it doesn't always do it quickly.
What happens after I remove time machine snapshots?
You can't go back to those exact moments from this Mac. Backups on your external drive or network are not touched.
Will time machine snapshots come back?
Yes, while Time Machine is on. That's normal; TidyMac keeps an eye on the size.
How do I clean time machine snapshots manually?
Open Terminal and type: tmutil listlocalsnapshots / to see them. To thin them, type: sudo tmutil thinlocalsnapshots / 999999999999 4 and enter your password.