Time Machine Local Snapshots Eating Your Storage? Fix It Here

This is the storage problem most Mac users never know about. Even if you’ve never plugged in a backup drive, even if Time Machine has never successfully completed a backup, macOS is creating snapshots of your data on your internal disk. They’re invisible in Finder. They count toward used space. They can grow to 30GB or more.

Welcome to local snapshots, the most surprising source of System Data on a typical Mac.

What local snapshots actually are

When Time Machine wants to back up but can’t (drive unplugged, network share unreachable), macOS keeps a local APFS snapshot on your boot drive instead. The idea: when you eventually do connect a backup drive, Time Machine has the snapshot data ready to back up.

The snapshots use APFS’s copy-on-write feature, so initially they don’t actually take up much space — they’re just references to existing files. As you modify files over time, the snapshots accumulate divergent data. After a few weeks, a single snapshot can be several GB.

macOS keeps roughly the last 24 hourly snapshots, plus daily snapshots for older periods. On a Mac that’s been running for months without a successful Time Machine backup, this can pile up to 30GB+.

Checking what you’ve got

Open Terminal and run:

tmutil listlocalsnapshots /

You’ll see output like:

Snapshots for volume group containing disk /:
com.apple.TimeMachine.2024-10-30-091523.local
com.apple.TimeMachine.2024-10-30-100412.local
com.apple.TimeMachine.2024-10-30-105023.local
...

Each entry is one snapshot, named with its creation timestamp. To see how much space they’re collectively using:

diskutil apfs list | grep -A 2 "Snapshot"

You can also get a clearer picture in Disk Utility:

1. Open Disk Utility
2. Select your Macintosh HD volume
3. View menu → Show APFS Snapshots
4. The bottom panel now shows all snapshots with size info

This is the easiest visual way to see what’s taking space.

Reclaim 20+ gigs in one passSweep finds the caches, snapshots, and old downloads adding up to most of your “System Data.” Free download →

How to delete snapshots

Several options depending on how aggressive you want to be.

Option 1: Force aggressive thinning. This is the easiest, fastest method:

sudo tmutil thinlocalsnapshots / 9999999999 4

The big number (free space target) is impossibly high, so macOS deletes everything it can. The 4 is urgency level (1-4, with 4 being highest). Expect to free 5-30GB instantly.

Option 2: Delete specific snapshots. If you want surgical control:

tmutil deletelocalsnapshots <date>

Where <date> is one of the timestamps from tmutil listlocalsnapshots. Format example: 2024-10-30-091523.

Option 3: Delete all snapshots:

sudo tmutil deletelocalsnapshots /

Removes every snapshot in one go. Same end result as Option 1.

Option 4: From Disk Utility’s GUI. In the snapshots view, select a snapshot and click the minus button. Good if you’re not comfortable with Terminal.

After any of these, the freed space should appear in your storage immediately. You can verify with df -h in Terminal or by checking System Settings → Storage.

Why they keep coming back

If you delete snapshots and they reappear within a day, that’s normal. macOS recreates them at the next scheduled backup attempt — typically every hour while your Mac is awake.

To stop them from being created at all, you have a few options:

• Disable Time Machine: System Settings → General → Time Machine → click the small button → Remove Backup Disk (or just toggle Time Machine off entirely if no disk is configured).
• Connect a Time Machine drive and let backups complete normally: macOS converts local snapshots to actual backups on the external drive, then thins the local ones aggressively.
• Reduce snapshot frequency by adjusting Time Machine’s behavior. There’s no UI for this, but you can disable automatic backups: sudo tmutil disable.

For most people, disabling Time Machine entirely is overkill — local snapshots really are useful as a recovery option for accidentally deleted files. Just thin them periodically.

When snapshots help vs. hurt

Worth knowing the upsides before nuking them:

• They’re a free safety net. If you accidentally delete a file or overwrite something important, you can browse to a snapshot and recover.
• Time Machine uses them as the backup source. Backing up from a snapshot means consistent data, not files mid-modification.
• They don’t hurt SSD health. Some folks worry about snapshot writes wearing out the drive — they’re trivial compared to normal use.

The downsides:

• They use disk space silently. This is the main complaint.
• They don’t auto-clear when storage gets tight unless you’re really tight. macOS waits until things get critical.
• They’re invisible in Finder. You can’t see them through normal interfaces.

For storage-constrained Macs, the right move is periodic thinning rather than disabling Time Machine entirely.

Snapshots from macOS updates

Beyond Time Machine snapshots, macOS itself creates a snapshot before applying any system update. The pre-update snapshot is the rollback point if the update fails.

These are at /private/var/.snapshot/ (you usually can’t see them) and labeled differently:

tmutil listlocalsnapshots /

If you see anything labeled com.apple.os.update-..., that’s an update snapshot. macOS auto-deletes these after the update is confirmed successful, but if you’ve recently updated, they might still be hanging around.

To delete an update snapshot:

sudo tmutil deletelocalsnapshots <update-snapshot-name>

Use this only if your macOS update went through cleanly and you don’t need a rollback option.

Verify the freed space

After thinning, check that the space actually came back:

df -h /

You should see a higher “Avail” number than before. Or check System Settings → Storage. The bar updates within a minute or two.

If the space didn’t free up, try:

1. Restart the Mac (forces some cleanup)
2. Run sudo tmutil thinlocalsnapshots / 9999999999 4 again
3. Check if Time Machine is mid-backup (the backup might be regenerating snapshots in real-time)

Make this a one-click jobSweep does the same hunt in seconds. Always shows you what’s about to go. Free for macOS →

Adding this to a routine

Local snapshots regrow within hours of clearing. You can either:

• Set a calendar reminder to thin them monthly
• Just thin them whenever you notice storage getting tight
• Use a tool that handles it as part of regular cleanup

Sweep includes snapshot cleanup in its scans — you see what’s there before deleting, and one click thins everything. Manual is also fine if you don’t mind opening Terminal occasionally.

What NOT to do with snapshots

A few things worth avoiding:

• Don’t disable APFS snapshots entirely. macOS uses them for system update rollback, software install rollback, and several other safety mechanisms. Disabling breaks these.
• Don’t try to delete snapshots from Finder. They’re not visible there, and the workarounds you’ll find in random forum posts can corrupt your filesystem.
• Don’t mount and tinker with snapshots manually. They’re meant to be read-only restore points. Modifying them risks data loss.
• Don’t believe articles that claim snapshots are “spying on you.” They’re a backup/recovery feature. They don’t transmit anywhere.

Quick summary for the impatient

If you’re just here to fix the problem fast:

1. Open Terminal
2. Run: sudo tmutil thinlocalsnapshots / 9999999999 4
3. Enter your password
4. Wait 30 seconds
5. Check Storage — space should be freed

That’s the whole fix. Repeat monthly. macOS recreates snapshots between thinnings, but you can keep them under control without doing anything more elaborate.

For most users, local snapshots account for 5-30GB of mysterious storage usage at any given time. Knowing the tmutil command is one of the highest-value things you can learn for managing Mac storage. It’s not buried in any Apple documentation that’s easy to find — most people only learn about it after frustrated googling.