What is purgeable space on a Mac?

In Finder’s Get Info window or in Disk Utility, you may see something like “180 GB available (45 GB purgeable)”. Purgeable space is data that is on your disk right now, but that macOS can remove by itself when it needs the room.

What counts as purgeable

Local Time Machine snapshots
iCloud Drive files that are also stored in iCloud, when Optimise Mac Storage is on
Caches and downloaded content that macOS and apps can fetch or rebuild again

macOS treats this space as available, so most apps can use it without you doing anything.

Why it doesn’t always clear

macOS frees purgeable space when space actually runs low, not ahead of time. Most apps are fine with that. Some installers and tools only count truly empty space, though, and then report that the disk is full even though Finder shows plenty available.

How to free it yourself

Local Time Machine snapshots are often the largest part. List them in Terminal:

$ tmutil listlocalsnapshots /

Then delete each one by its date. macOS asks for your password. Your backups on the Time Machine drive stay as they are.

$ sudo tmutil deletelocalsnapshots 2026-10-29-120000

For iCloud Drive files you don’t need offline, select them in Finder, Control-click and choose Remove Download. They stay in iCloud.
Restart your Mac so macOS can clear temporary data it was holding on to.

See it in OpenDisk

When you scan a whole disk, OpenDisk shows purgeable space as its own slice next to free space. That way you can tell how much of the disk is really in use and how much macOS can give back.