Time Machine local snapshots taking up space? What to do
If you use Time Machine, your Mac also keeps snapshots on its own disk. They're useful, they're temporary — and they're one reason freed space doesn't show up right away.
What local snapshots are
With Time Machine turned on, macOS takes a snapshot of your startup disk about every hour and keeps it for roughly a day. If your backup disk isn't connected, you can still restore a file you changed or deleted a few hours ago.
A snapshot keeps old versions of changed and deleted files. That's why deleting a large file sometimes doesn't free space at once: the snapshot still holds it until the snapshot expires. Snapshots count as purgeable space and show up in System Data.
See your snapshots
Open Terminal and run:
tmutil listlocalsnapshots /
Each line is one snapshot, named with its date and time (for example com.apple.TimeMachine.2026-10-01-101500.local).
Delete them (only if you need the space now)
macOS deletes local snapshots automatically when disk space runs low, so usually you don't need to do anything. If you need the space right away — say, for a large install — delete a snapshot by its date:
sudo tmutil deletelocalsnapshots 2026-10-01-101500
You'll lose the ability to restore from that snapshot, but your Time Machine backups on the backup disk are unaffected.
How they look in DiskGarden
Snapshot space isn't part of any folder, so a normal scan can't attribute it. DiskGarden shows it as part of the purple hidden space petal, and the Free + purgeable figure tells you how much macOS can reclaim on its own.
See where your space went
DiskGarden is a free disk space analyzer for Mac: it maps every folder by size, so the space hogs stand out. No account, and your files never leave your Mac.