Free up storage
How to Find Hidden Time Machine Local Snapshots on Your Mac
Find every Time Machine local snapshot on your Mac's internal drive. List, inspect, and delete the hidden snapshots eating tens of gigabytes.
Time Machine doesn’t only back up to your external drive. macOS also keeps “local snapshots” of your drive on the internal SSD itself, taken hourly, retained for up to 24 hours. They exist as APFS filesystem snapshots — invisible to Finder, completely hidden from Storage settings in any actionable way, but real on your disk.
A typical local snapshot can hold 5-30GB of data, depending on how much your files change in an hour. With 24 hours of retention plus a few daily/weekly snapshots, you can have 100GB of snapshots eating space without realizing.
Here’s how to find every snapshot, see what they contain, and clear them safely.
What a local snapshot actually is
When Time Machine takes a backup, it first creates an APFS snapshot — a frozen copy of the filesystem at that moment. Then it copies changed files to your external drive. The snapshot lets the backup happen against a consistent state even while you’re still using the Mac.
After the backup completes, the snapshot doesn’t disappear. macOS keeps it as a “local snapshot” — useful if you want to restore individual files without your external drive connected.
If no external Time Machine drive is connected for a while, macOS still creates these local snapshots hourly. They accumulate until 24 hours, then start rotating out as new ones replace old.
Listing every snapshot
The one essential command:
tmutil listlocalsnapshots /
Output looks like:
com.apple.TimeMachine.2025-10-12-080000.local
com.apple.TimeMachine.2025-10-12-090000.local
com.apple.TimeMachine.2025-10-12-100000.local
...
Each line is one snapshot, named with the date and hour it was taken. On a typical Mac with Time Machine set up, you’ll see 12-24 snapshots.
For external Time Machine drives:
tmutil listbackups
Different list — those are full backups on the external. Local snapshots are different.
com.apple.TimeMachine.YYYY-MM-DD-HHMMSS.local. The HHMMSS is the hour, minute, second the snapshot was taken — almost always on the hour for Time Machine.Seeing snapshot disk usage
Snapshots aren’t easy to size individually because they share data with the live filesystem. APFS uses copy-on-write — a snapshot uses zero space until the live filesystem diverges from it.
For an approximate per-snapshot size, you can query APFS metadata:
diskutil apfs list
Output includes “Snapshot” entries. Look for size fields, but be aware: a snapshot showing “10GB” usually means it represents 10GB of data that has changed in the live filesystem since the snapshot was taken.
For total snapshot usage:
diskutil info / | grep -i "Snapshot"
Shows snapshot-related disk usage on your boot volume.
The number you usually care about is “purgeable” space, which is dominated by snapshots:
diskutil info /
Look for a line about purgeable or available. The big purgeable number on most Macs IS the snapshots.
How long snapshots are kept
Default behavior:
- Hourly snapshots: kept for 24 hours
- Daily snapshots: kept for the past month (only if your Mac has been on for that long)
- Weekly snapshots: kept until space pressure
Apple’s stated rule: snapshots are deleted when your free space drops below 20%. In practice, snapshots can hang around longer, especially if your free space rarely dips that low.
To check what’s currently set:
defaults read /Library/Preferences/com.apple.TimeMachine
That dumps the Time Machine plist. Look for keys like MobileBackups, LocalSnapshots, SkipPaths.
Deleting a specific snapshot
To delete one snapshot by name:
sudo tmutil deletelocalsnapshots 2025-10-12-080000
Note the date format — just the date and time portion, no .local suffix. The full snapshot path is implied.
You’ll be asked for your admin password.
To delete a few at once:
for snap in 2025-10-10-080000 2025-10-10-090000 2025-10-10-100000; do
sudo tmutil deletelocalsnapshots $snap
done
Adjust dates to match your actual snapshot names from tmutil listlocalsnapshots /.
Bulk deletion via thinning
For aggressive cleanup, ask macOS to thin all snapshots:
sudo tmutil thinlocalsnapshots / 999999999999 4
The arguments:
/— target volume999999999999— target free space in bytes (essentially unlimited, so thin all)4— urgency level (1-4, higher = more aggressive)
This requests macOS prune snapshots until free space increases by the target amount. Level 4 thins everything beyond what’s strictly needed.
After running, re-check with tmutil listlocalsnapshots /. You’ll typically see only the most recent 1-3 snapshots remaining.
Disabling local snapshots entirely
If you don’t want them at all:
sudo tmutil disable
That turns off Time Machine entirely (including external backup if you have one). Probably not what you want.
For just disabling local snapshots while keeping external backups, the command varies by macOS version. On modern macOS, the cleanest path:
System Settings → General → Time Machine → Options. Look for snapshot-related options. Some macOS versions expose this; others don’t.
If snapshot creation is itself the problem (rare), you can prevent backups from running:
sudo tmutil stopbackup
Stops a currently-running backup. Doesn’t prevent future ones — those run on Time Machine’s schedule.
Why this matters for storage
After cleaning files manually and not seeing free space increase, the cause is often snapshots.
Example: you delete 30GB of old files. Storage settings shows the same available space as before. Why?
Because those 30GB still exist in the most recent snapshot. APFS keeps the data referenced by snapshots even though you “deleted” it from the live filesystem. Your live data went down 30GB, but snapshot-held data went up 30GB.
The space is purgeable — macOS will release it under pressure. But if you want immediate free space after manual deletion, force a snapshot thin.
When deletion feels stuck
Sometimes tmutil thinlocalsnapshots runs but doesn’t appear to free space. A few reasons:
Time Machine is running. Wait for the current backup to finish before thinning.
A new snapshot was just created. New snapshots are protected briefly. Wait an hour and try again.
Disk Utility is open. Some operations conflict.
System Integrity Protection. Snapshots used as “Sealed System Snapshot” for macOS itself can’t be removed by any user command. These are different from Time Machine snapshots and shouldn’t appear in tmutil listlocalsnapshots.
For a stuck case:
- Restart the Mac
- Run
tmutil listlocalsnapshots /again - Try deletion or thinning fresh
Reboots resolve weird snapshot states more often than you’d expect.
Snapshots and external backups
A common confusion: people think deleting local snapshots affects their external Time Machine backup. It doesn’t.
Local snapshots are on your internal drive. External backups are on your external drive. They’re related (Time Machine creates both from the same source) but independent.
You can:
- Delete all local snapshots — external backup unaffected
- Delete external backups — local snapshots unaffected
- Have only one, or both, or neither
The Time Machine UI in System Settings shows external backup status. Local snapshots are essentially invisible to that UI.
Performance during snapshot creation
When Time Machine takes a snapshot, your Mac may briefly slow down — usually a few seconds. The snapshot operation is fast on APFS, but during it, the filesystem freezes momentarily.
If you notice your Mac stutters once an hour, on the hour, that’s likely Time Machine snapshot creation.
To verify:
log show --predicate 'subsystem == "com.apple.TimeMachine"' --last 1h
Shows recent Time Machine activity, including snapshot operations.
For Macs where this is annoying, the fix is to disable Time Machine entirely (rare) or accept the brief pauses.
Diagnostic snapshots
Beyond Time Machine, macOS occasionally creates other snapshots — for system updates, for boot integrity, for diagnostic purposes. These have different naming patterns:
diskutil apfs list
Lists ALL APFS snapshots, including non-Time Machine ones. Most users will see only Time Machine snapshots and the Sealed System Snapshot. The Sealed System Snapshot is part of macOS — don’t try to delete it.
System update snapshots appear briefly during updates. They clean themselves up.
A regular maintenance pattern
For most users, snapshots take care of themselves. They rotate out automatically.
The maintenance points:
- Before a big install or download, thin snapshots to ensure max free space:
sudo tmutil thinlocalsnapshots / 999999999999 4 - After deleting large files, thin to actually free the space:
sudo tmutil thinlocalsnapshots / 999999999999 4 - If Storage settings is mysteriously full, list snapshots:
Multiple GB of snapshot space may be the explanation.tmutil listlocalsnapshots /
A cleaning tool typically includes snapshot management as part of cleanup. Combined with manual tmutil commands, you can keep snapshot space in control.
The biggest insight here is just knowing snapshots exist. Macs that mysteriously have less space than expected, where deletion doesn’t seem to help, are usually Macs with a lot of snapshot accumulation. One thinning command often returns 30+ GB of “missing” space immediately.