Why Time Machine Snapshots Are Taking Up 20–80 GB on Your Mac

The Hidden Space macOS Never Tells You About

Open About This Mac → Storage and you'll see a breakdown of what's using your disk. But this view is lying to you — by omission. Somewhere between 20 and 80 GB of your disk is held in local APFS snapshots that macOS creates automatically, and Finder refuses to clean them.

What Are Local APFS Snapshots?

When Time Machine runs a backup, macOS creates a local point-in-time snapshot of your APFS volume first. This lets Time Machine do an efficient incremental backup in the background. The snapshots are also created before major OS updates as a safety net.

These snapshots appear as purgeable space in macOS's storage report, but "purgeable" doesn't mean macOS will reclaim it automatically. They can persist for weeks.

How to Audit Your Snapshots

# List all local snapshots
tmutil listlocalsnapshots /

# Get their sizes (requires sudo)
tmutil listlocalsnapshotdates / | while read date; do
  tmutil localsnapshot / "$date"
done

You'll typically see snapshots with timestamps from the last 7–30 days, each consuming several gigabytes.

How to Delete Them Safely

# Delete a specific snapshot by timestamp
tmutil deletelocalsnapshots 2026-09-15-120000

# Delete ALL local snapshots (aggressive)
for snap in $(tmutil listlocalsnapshotdates | grep -v '^$'); do
  tmutil deletelocalsnapshots "$snap"
done

Note: Deleting local snapshots does NOT affect your Time Machine backup drive. They are local disk copies only.

How MacPilot Handles This

MacPilot's Storage Intelligence panel surfaces all local APFS snapshots with their creation date, size, and a one-click safe deletion. It uses the same tmutil and fsctl APIs that macOS itself uses — no dangerous third-party kernel extensions required.