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Time Machine local snapshots: are they eating your storage?
When automatic backups are on, Time Machine saves a local snapshot about every hour on your Mac's own disk. Each one is kept for up to 24 hours, and macOS removes them on its own when space is needed. Apple counts that space as available. Most of the time you don't need to do anything. If an install or a big copy still fails for lack of space, turn Back Up Automatically off for a few minutes, or delete snapshots with tmutil.
What local snapshots are
Time Machine normally backs up to an external drive or a network disk. So that you can still restore files when that disk isn't connected, it also keeps local snapshots on your Mac. According to Apple:
- Time Machine saves one snapshot of your startup disk about every hour.
- Each snapshot is kept for up to 24 hours. One extra snapshot of your last successful backup is kept until space is needed.
- Another snapshot is saved before a macOS update is installed.
- Snapshots are only made on disks formatted as APFS, and only when Back Up Automatically is on.
Local snapshots are a convenience, not a backup. They live on the same disk as your files, so they don't help if that disk fails.
Do they really take up space?
They do use space on the disk, but Apple says your Mac counts the space used by snapshots as available storage, and Time Machine deletes them as they age or when other tasks need the room. That is why the free space in System Settings can look larger than what some other tools report.
In practice this rarely causes trouble. When it does, it's usually right after a large clean-up: you deleted gigabytes of files, but they are still held by a recent snapshot, so the space comes back only when that snapshot expires.
How to see your snapshots
Open Terminal (in Applications › Utilities) and run:
tmutil listlocalsnapshots /
Each line ends with a date, such as 2026-10-29-101500. No output means there are no local snapshots on your startup disk.
How to remove them
The Apple way: pause automatic backups
- Open Apple menu › System Settings › General › Time Machine.
- Turn off automatic backups and wait a few minutes. macOS removes the local snapshots.
- Turn automatic backups back on. Time Machine remembers your backup disks.
The Terminal way: delete one snapshot
sudo tmutil deletelocalsnapshots 2026-10-29-101500
Replace the date with one from your list. Terminal asks for your Mac password and shows nothing while you type it. Backups on your external Time Machine disk are not affected.
What not to do
- Don't turn Time Machine off for good just to save space. You lose your backups, and snapshots go away on their own anyway.
- Don't delete files inside
/Systemor/private/var. Use the steps above instead. - Don't rely on snapshots as your backup. Keep regular backups on another disk.
Where Tidymint fits
We leave Time Machine snapshots to macOS on purpose: they expire on their own, and removing them is a backup decision, not a clean-up one. Tidymint focuses on what macOS won't clear for you: app and browser caches, logs, old downloads, leftovers from deleted apps, large and duplicate files. Space Lens shows where the rest of your disk went. Everything always goes to the Trash first.
Doing it by hand vs. Tidymint
| By hand | Tidymint | |
|---|---|---|
| Speed | Open hidden folders one by one, type Terminal commands | One scan, results grouped by size |
| The big picture | You see one folder at a time | Space Lens shows the whole drive and the heaviest folders |
| Understanding your Mac | Cryptic folder names like Caches and DerivedData | Plain-language notes for common folders |
| No accidental deletes | A wrong delete is gone for good | Safe items pre-selected, the rest left to you, always to the Trash first, with Undo |
| Cost | Free, but it takes time | Free and open source |
Clean your Mac for free
Tidymint is free and open source. Everything always goes to the Trash first, so you stay in control.
FAQ
Is it safe to delete Time Machine local snapshots?
Yes. They are short-term copies on your Mac's own disk. Deleting them does not touch the backups on your Time Machine drive. You only lose the option to restore from that hour while the drive is disconnected.
How long does macOS keep local snapshots?
Up to 24 hours each, plus one snapshot of your last successful backup until space is needed. macOS also deletes them early when the disk needs room.
Why didn't I get space back after deleting files?
A recent local snapshot may still hold those files. The space returns when the snapshot expires, or right away if you remove local snapshots.
Do local snapshots show up as System Data?
Apple says the space used by snapshots is counted as available storage. If System Data is large, the usual causes are caches, old iPhone backups and developer files.
Does Tidymint delete Time Machine snapshots?
No. Tidymint leaves them to macOS and focuses on caches, logs, old downloads, app leftovers, large files and duplicates.
Doing it by hand vs. Tidymint
| By hand | Tidymint | |
|---|---|---|
| Speed | Open hidden folders one by one, type Terminal commands | One scan, results grouped by size |
| The big picture | You see one folder at a time | Space Lens shows the whole drive and the heaviest folders |
| Understanding your Mac | Cryptic folder names like Caches and DerivedData | Plain-language notes for common folders |
| No accidental deletes | A wrong delete is gone for good | Safe items pre-selected, the rest left to you, always to the Trash first, with Undo |
| Cost | Free, but it takes time | Free and open source |
Clean your Mac for free
Tidymint is free and open source. Everything always goes to the Trash first, so you stay in control.
Sources
- Apple: About Time Machine local snapshots
- Apple Mac User Guide: About Time Machine local snapshots on Mac
- Apple Community: How to delete Time Machine local snapshots
