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The invisible backups eating your disk: how to delete Time Machine local snapshots

Updated September 2026 · 7 min read

Your Mac says the disk is almost full, but you can't find anything big in Finder. You've emptied Trash, deleted old movies, and nothing changed. The most likely culprit? Time Machine local snapshots — backup copies macOS quietly keeps on your startup disk, completely invisible in Finder.

They're useful, they're well-intentioned, and they can easily swallow 10–50 GB without you ever knowing. Here's how to find them, how to safely remove them, and — just as important — when to leave them alone.

What are local snapshots, exactly?

When Time Machine is turned on, macOS doesn't just back up to your external drive. It also saves periodic snapshots of your files directly on your startup disk. These snapshots act as a local safety net: if you accidentally delete a file and your backup drive isn't plugged in, you can still recover it from a recent snapshot.

macOS creates a new snapshot roughly every hour. Old ones get deleted automatically — eventually. But "eventually" can mean days or weeks, and on a smaller SSD, the snapshots pile up fast.

Why you can't see them in Finder

Local snapshots are stored in a system-level layer called APFS snapshots. They don't appear in any Finder window, they aren't in ~/Library, and they don't show up in "About This Mac → Storage" as a separate category. macOS folds them into "System Data" or "macOS" — the same vague buckets that tell you nothing.

This is why you can have 40 GB of snapshots and honestly believe your disk is full of mystery files. It's not a bug — it's just bad labeling. If your System Data category looks suspiciously huge, snapshots are often the biggest chunk inside it.

How to check what's there

Open Terminal (it's in Applications → Utilities) and type:

tmutil listlocalsnapshots /

You'll see a list like this:

Each line is one snapshot. The date tells you when it was taken. If you see many of them stretching back days or weeks, they're collectively using real storage.

How to delete specific snapshots

Pick a snapshot date from the list and run:

tmutil deletelocalsnapshots 2026-08-28-140532

That's it. The snapshot is gone, and you get the space back immediately. Repeat for as many snapshots as you want to remove.

If you'd rather trim them all at once instead of deleting one by one, there's a gentler option:

tmutil thinlocalsnapshots / 10000000000 4

This tells macOS to thin snapshots until at least ~10 GB of space is freed, with an urgency level of 4 (highest). macOS decides which snapshots to drop, keeping the most recent ones. It's less precise but safer — you don't accidentally remove the one snapshot you might need.

When NOT to delete snapshots: if you don't have any other backup — no external drive, no Time Machine over network, no cloud backup — local snapshots are your only way to recover deleted files. In that case, don't touch them. Instead, get a backup set up first (even a cheap USB drive works), and then clean up.

Will they come back?

Yes. As long as Time Machine is turned on, macOS will keep creating new local snapshots. This is normal and by design. The difference is that now you know where to look when your disk fills up again.

If you want to stop local snapshots entirely, you can turn off Time Machine in System Settings → General → Time Machine. But this also stops your actual backups, so it's rarely a good trade-off. A better approach: just check your snapshots every few months and thin them if needed.

How much space will you actually recover?

It depends on how long the snapshots have been piling up and how much your files have changed. On a Mac that hasn't been backed up to an external drive in weeks, 20–40 GB is common. On one that backs up nightly, you might free only 3–5 GB. Either way, it's the first thing to check when your Mac complains about disk space — especially if you can't figure out where the storage went.

Or let Gigatidy find them for you

Gigatidy spots local snapshots, explains how much space they hold, and clears only the ones you approve — no Terminal needed.

Meet Gigatidy →

FAQ

Can deleting local snapshots cause data loss?

No — unless those snapshots are your only backup. They're extra copies of files you already have. If you also use Time Machine with an external drive or any other backup method, deleting local snapshots is completely safe.

Why doesn't macOS delete old snapshots automatically?

It does, but only when disk space gets critically low. macOS prioritizes keeping snapshots "just in case" over freeing space proactively, which means they can grow large before the system steps in.

Do local snapshots slow down my Mac?

The snapshots themselves don't slow anything. But if they push your disk usage above 85–90%, macOS starts struggling with memory swap and temporary files — and that definitely slows things down. Freeing snapshot space removes the bottleneck.