Mac storage basics · Disks, APFS and formats

What are the Preboot, Recovery, VM and Update volumes in Disk Utility?

Short answer: They're small system volumes macOS manages: Preboot for startup, Recovery for repairs, VM for swap and sleep files, Update for installs. Leave them alone.

They're small system volumes that live in the same APFS container as your Macintosh HD:

  • Preboot — files needed to start up, including for FileVault.
  • Recovery — macOS Recovery, used for repairs and reinstalling.
  • VM — swap and sleep files.
  • Update — used while installing macOS updates.

macOS manages them; don't delete or reformat them. They share the container's free space with your data, which is why the numbers in Disk Utility don't add up to one simple figure. Background: APFS containers and volumes.

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