Time Machine local snapshots: what they are and how to delete them

What local snapshots are

A local snapshot is a read-only record of your startup disk at one moment, made with APFS, the file system Macs use. Time Machine makes them so you can get back a file you changed or deleted in the last day, even when your backup disk isn't connected.

Apple's snapshot article lays out the schedule:

• Time Machine saves a snapshot of your startup disk about every hour and keeps it for 24 hours.
• It keeps one more snapshot of your last successful Time Machine backup until space is needed.
• It also saves a snapshot before installing any macOS update.

Snapshots are made only on APFS disks, and only while automatic backups are on. Apple adds that Time Machine stores them only on disks with plenty of free space, and that it deletes them as they age or as space is needed for other things. Your Mac counts the space they use as available storage.

Where local snapshots are stored

On the same disk as the files they protect. A snapshot isn't a file or a folder you can open in Finder; it's part of the APFS volume itself. Apple's Mac User Guide also points out that snapshots are separate from the backups on your Time Machine disk. When your backup disk isn't available, Time Machine uses local snapshots to help you restore files.

A snapshot doesn't copy your disk. At first it shares everything with your current files and takes almost no space. It grows as you change and delete things, because it keeps the old versions. That's why deleting a large file sometimes frees nothing for a day: the most recent snapshot still holds it.

How to see your local snapshots

Terminal lists them by name:

tmutil listlocalsnapshots /

The output looks like this, one line per snapshot, named with the date and time it was made:

Snapshots for disk /:
com.apple.TimeMachine.2026-10-22-091512.local
com.apple.TimeMachine.2026-10-22-101544.local

For just the dates, use tmutil listlocalsnapshotdates /. An empty list means there are no local Time Machine snapshots on that disk.

Disk Utility shows them with sizes. Open Disk Utility, choose View > Show APFS Snapshots, and select your Data volume, usually called Macintosh HD - Data, in the sidebar. A table at the bottom lists each snapshot. Apple's Disk Utility guide lists the columns you can show, including Date Created, Private Size and Cumulative Size.

How much space local snapshots use

There's no typical size. A snapshot costs only what has changed since it was made. If you edited a few documents, it's small. If you downloaded and then deleted a big video, or an app rewrote a large database, it can hold many gigabytes.

In Disk Utility, Private Size is the space held by that snapshot alone, roughly what removing it would free. Snapshots often share data with each other, so adding up their sizes overstates the total.

Because Apple counts this space as available, System Settings won't warn you about it. It usually shows up inside System Data, as described in System Data on a Mac, and as purgeable space in Disk Utility, covered in purgeable space on a Mac.

Why snapshots make free space look wrong

Snapshots are behind many "I deleted it and nothing changed" moments. Say you empty the Trash after moving a large folder of videos to it. System Settings counts snapshot space as available, so it shows the space back. Terminal's df and Disk Utility's free figure don't, because the most recent snapshot still holds those videos. Two tools, two answers, both correct by their own rules. The gap closes when the snapshot ages out or when you remove it. Why Mac storage doesn't add up covers this and the other usual reasons.

Snapshots on external drives

Time Machine makes local snapshots of every APFS volume it backs up, not only the startup disk. A snapshot on an external drive uses that drive's space. To list them, give the drive's mount point instead of /, replacing Projects with your drive's name:

tmutil listlocalsnapshots /Volumes/Projects

How to delete local snapshots

You rarely need to. macOS removes snapshots after a day, and sooner when something needs the space. If you need the room now, or an update won't install, Apple's method is to pause automatic backups for a few minutes:

1. 1

   Open Time Machine settings

   Choose Apple menu > System Settings, click General in the sidebar, then click Time Machine.

2. 2

   Open Options

   Click Options to see how often Time Machine backs up.

3. 3

   Set Backup Frequency to Manually

   Choose Manually from the Backup Frequency menu, then click Done. Time Machine stops making hourly snapshots and starts removing the ones it has.

4. 4

   Wait a few minutes

   Give macOS a few minutes. In Terminal, tmutil listlocalsnapshots / shows whether any are left.

5. 5

   Turn automatic backups back on

   Open Options again and set Backup Frequency back to Automatically Every Hour, or what you used before, then click Done.

Before you start, connect your backup disk and choose Back Up Now from the Time Machine menu, so nothing from the last day exists only in a snapshot. While Backup Frequency is set to Manually, your Mac doesn't back up on its own.

Delete Time Machine snapshots in Terminal

tmutil is Time Machine's own command-line tool. To remove every local Time Machine snapshot on the startup disk:

tmutil deletelocalsnapshots /

To remove a single snapshot, give its date and time as it appears in the list:

tmutil deletelocalsnapshots 2026-10-22-091512

The tmutil manual says a date removes the local snapshots with that date on all mounted disks. To have Time Machine free a set amount instead, give it a mount point and a number of bytes. This asks for 20 GB:

tmutil thinlocalsnapshots / 20000000000

All three remove snapshots permanently. They don't go to the Trash and can't be undone, though your backups on the Time Machine disk aren't affected. If Terminal reports that the operation isn't permitted, run the same command with sudo in front and enter your administrator password.

Disk Utility can do the same: select one or more snapshots in the table and click the Delete Snapshot button. That's permanent too.

Can you turn local snapshots off?

Not on their own. The tmutil manual on current macOS lists verbs to create, list, delete and thin local snapshots, but none to disable them. Time Machine makes them only while automatic backups are on, so the only way to stop them is to set Backup Frequency to Manually. That also stops automatic backups, which is a poor trade for most people. If snapshots keep crowding a nearly full disk, the lasting fix is more free space, so macOS doesn't have to keep giving it back.

Is it safe to delete local Time Machine snapshots?

Yes, with one check first: your Time Machine backups should be current. Here's what deleting them does and doesn't do.

• It doesn't touch your backups. Backups on your Time Machine disk stay as they are.
• You lose the last day of hourly versions on the Mac. If you haven't connected your backup disk for a while, a snapshot may hold changes that aren't backed up yet, so back up first.
• It's temporary. Time Machine makes a new snapshot within the hour.

Other snapshots you might see

Disk Utility can show snapshots that aren't from Time Machine. If you select the macOS volume rather than the Data volume, you may see one named com.apple.os.update- followed by a long code. It belongs to the signed system volume, the sealed, read-only copy of macOS, which Apple's platform security guide says uses APFS snapshots. Leave it alone. Some third-party backup apps make their own snapshots too. tmutil handles only Time Machine's, so manage those in the app that made them.

How MacClearings handles local snapshots

MacClearings explains snapshots and leaves them to macOS. Breakdown reads them with tmutil listlocalsnapshots and lists them under "What MacClearings can't see": how many there are, when the oldest was made, why Time Machine and macOS updates keep them, and that macOS frees them after about a day, or sooner when space runs low. They carry a "Frees on its own" label, and Breakdown never offers them as a cleanup or changes them.

When you do want space back, Suggestions lists things that don't return on their own, like Xcode build data and old downloads, each with a plain reason. You review everything first, MacClearings moves what you confirm to the Trash, and History can undo any cleanup. The space comes back when you empty the Trash, which MacClearings never does for you.