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Time Machine local snapshots are taking space on my Mac

Published 2026-11-11

Local snapshots are restore points that macOS keeps on your own disk, so you can recover a file from earlier today even when the backup drive is not plugged in. They are APFS snapshots. A snapshot holds on to files you have since deleted or changed, so space does not come back when you delete things. macOS deletes them itself after about 24 hours or when it needs room, and you can remove them sooner with tmutil. Many Macs have none, and the number alone tells you nothing about size.

See whether you have any

tmutil listlocalsnapshots /

With snapshots, the output looks like this:

Snapshots for disk /:
com.apple.TimeMachine.2026-11-11-093012.local
com.apple.TimeMachine.2026-11-11-103015.local

On a Mac with no Time Machine snapshots it prints only the header line. tmutil listlocalsnapshotdates / prints just the dates. The date in each name (2026-11-11-093012) is what the delete command takes. These are made roughly hourly when Time Machine backups are turned on, and macOS keeps them for up to 24 hours.

The second check lists every APFS snapshot on the data volume, including ones that are not Time Machine's:

diskutil apfs listSnapshots /System/Volumes/Data

It prints No snapshots for disk3s5 when there are none (the disk name differs per Mac). Run this one, because tmutil does not list the others. macOS software updates create their own snapshots (named com.apple.os.update-...), and some third-party backup tools such as Carbon Copy Cloner create theirs. The boot volume also always shows one snapshot, the sealed system snapshot mounted at /. That one is part of how macOS boots. Do not touch it, and you cannot with tmutil anyway.

What size is a snapshot?

You cannot find out. tmutil reports names and dates and no sizes, and macOS does not publish a size for one snapshot. A snapshot's cost is the data that exists only in it: files you deleted or edited since it was taken. A snapshot taken a minute ago on an idle Mac costs almost nothing. One from yesterday on a Mac where you moved a 30 GB video holds up to 30 GB.

The practical sign is a mismatch. The files in your folders add up to less than the used figure, and System Data is large. See What is System Data on Mac.

Confirm snapshots are the cause

Snapshots are one of several things that make used space exceed what your folders add up to. Before you delete anything, rule out the others. Compare df -H /System/Volumes/Data (used) with du -sh ~ plus /Applications. A gap of tens of gigabytes with a snapshot list that is empty means the space is elsewhere: swap files and sleep images in /System/Volumes/VM, system caches, or protected folders that du could not read. A gap with a non-empty list is a reason to suspect snapshots, though it still does not prove it.

A direct test is to thin the snapshots (below) and watch whether the free figure moves. If it does not, snapshots were not the problem and nothing was lost.

Should you delete them?

Often not. Finder's free space figure counts snapshot space as available, because macOS releases it on demand (APFS calls this purgeable space). If a big file copy or an update needs room, macOS thins the snapshots itself. Deleting them by hand matters in three situations: a tool that reads free space without counting purgeable space refuses to start (some installers, virtual machine and video tools), you freed space on purpose and it is not appearing, or the disk is nearly full and you need the room now.

Remove or thin them

Delete one by its date. This needs administrator rights:

sudo tmutil deletelocalsnapshots 2026-11-11-093012

This removes that restore point and nothing else. Your files, your Time Machine drive and your backup history are untouched. The snapshot is not recoverable. The cost is that you can no longer restore the state of the disk at that time from the local copy. If your backup drive is attached and current, that is fine.

To ask macOS to reclaim a set amount, thin instead of deleting. The first number is bytes to reclaim, the second is urgency from 1 to 4:

sudo tmutil thinlocalsnapshots / 20000000000 4

That asks for 20 GB at the highest urgency. It removes snapshots until the target is met or none remain, which is what macOS does itself under pressure. If your snapshots hold less than the target, it removes them all and reports no error, so do not read success as 20 GB gained.

Making a new snapshot, tmutil localsnapshot, is the reverse. Do not run it while you are short of space.

What most articles get wrong

They say deleting local snapshots frees the space they show. It frees only blocks that no live file uses. A snapshot holds old versions of files and shares everything unchanged with the live disk. So the gain is the churn since the snapshot, which can be 200 MB or 30 GB. You cannot predict it in advance.

Many articles also say to turn local snapshots off with tmutil disablelocal. That command was removed in macOS High Sierra and does nothing on any current macOS. Snapshots appear when Time Machine has a backup destination and automatic backups on. If you do not use Time Machine, remove the destination in System Settings > General > Time Machine. The Mac used to check this guide has no destination and no snapshots.

A third: the free space figure lags. After removal, give Finder and Storage settings a minute or two, and check with df -h /System/Volumes/Data, not df -h /, which reports only the system volume.

Using Spotless for this

Spotless's System Data view counts your local snapshots and lists their dates. Its Delete All Snapshots button runs the same tmutil deletelocalsnapshots command after a confirmation and an administrator password prompt. Like the command, it cannot be undone, and it cannot say how much space you will get back, because macOS does not report snapshot sizes to apps. See System Data.

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