What are "Not Mounted" APFS volumes?

[rbpeirce]

I have a container that contains one volume that I know of. It mounts. However, Disk Utility for that container show 3 Not Mounted volumes. I can find no way to access them or to delete them.

 

[RadDave]

I have a container that contains one volume that I know of. It mounts. However, Disk Utility for that container show 3 Not Mounted volumes. I can find no way to access them or to delete them.

Hello - can you post a pic that shows your disk structure (like the one below of my laptop with two external devices mounted) - I'm assuming that you mean 'unmounted volumes' within the red box of my image. Also please provide your computer type and macOS installed - thanks. Dave
.

 

[MacInWin]

There are some reserved system volumes in Sonoma. Here is what my boot drive shows:



You can see there are 5 volumes in the Container. Macintosh HD and Macintosh HD - Data are the typical drives for system and user data. VM and Preboot are system volumes and cannot be removed or changed. The one not Mounted is, I think, Recovery.

Here is a fairly technical article on drive structures:

An atlas of recovery and boot volumes: High Sierra to Monterey

From High Sierra’s four-volume group to macOS 12 on Apple silicon with three containers and 11 volumes, and both regular and fallback Recovery volumes.

eclecticlight.co

 

[rbpeirce]

Hello - can you post a pic that shows your disk structure

 

[RadDave]

Well, tried to sharpen up your image below but your internal SSD is labelled 'Container disk1' but does not look quite like mine (again need more info on your computer and macOS installed).

Then there is an external Seagate 5TB APFS drive (don't know type) w/ a 'Container disk3' and a volume named 'Music' - there are two 'Eject' icons - can you unmount this drive?

Also in the View menu, do you have 'Show All Devices' checked? And hope that Jake returns to help you out. Dave

.

 

[MacInWin]

Was that disk ever used for something else? Is it bootable? I'm wondering if the other Volumes used to be used, but whatever created them no longer uses them.

 

[rbpeirce]

It is the music disk. It only contains the single container and volume but it shows three unmounted volumes and I can't identify or do anything with them. I used Attach files for the screen shot. I'll drag-and-drop it. Below Container disk3 it shows the blue bar for music and below it says 3 Not Mounted. What are they and is there a way to get rid of them? They don't really take up much space but they make it look like something isn't quite right.

 

[MacInWin]

Well, you could open Terminal, then issue "diskutil list" to get a listing of the drives. You should get something like this:



That's from my system. You can see that the listing shows my internal storage first, with three Containers, two of which are reserved for the system. The second listing is "/dev/disk3" and is the drive associated with my previous screenshot. It shows the Macintosh HD and Macintosh HD -- Data volumes, plus the Preboot and VM Volumes, plus the Recovery, which was not mounted in the earlier screenshot I posted.

Frankly, I wouldn't worry about it and wouldn't do anything about it unless the drive is performing strangely.