The following image shows my Disk Utility window.

Disk Utility

It says there are 5 volumes in total, but I can only access two: Macintosh HD and Macintosh HD - Data. Apparently one of them is a Virtual Machine as denoted by the VM. Another one of them is Recovery, but I do not know what this means exactly. The final volume is not mounted; it does not even mount after I click the Mount button.

Is there a way possibly through terminal or Recovery mode in where I can access them and determine if they are useful or not? I am running macOS Catalina on my 2015 iMac if that helps.

Thank you in advance!

  • 1
    Go into Terminal, issue the command diskutil apfs list and it will show you all the volumes. You really have no need to access any of them but every one of them is useful, like boot, Recovery, etc.
    – Allan
    Jul 10, 2020 at 23:59
  • 1
    What @Allan said. Those "invisible" volumes are useful only to macOS and are hidden so they are not changed accidentally. They hold boot information, virtual memory and a partition that you can boot from to repair or recover macOS should your install become damaged. The area marked free will shrink as you fill up your Mac HD. Jul 11, 2020 at 0:06

1 Answer 1


A typical APFS volume under Catalina will have 5 partitions.

  • Macintosh HD: the read-only volume that stores the OS
  • Macintosh HD - Data: the 'normal' everyday volume where you save stuff to.
  • Preboot: a small amount of data used ... before booting.
  • Recovery: the Recovery volume that you boot to when holding Command R
  • VM: caches for virtual memory.

These are all essential, and you should not need to access them or do anything else with them.

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