I have 21 disks after running “diskutil list”

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Level 1

14 points

I have 21 disks after running “diskutil list”

So when I boot into recovery mode and access terminal from there, and then run “diskutil list” the results show that I have 21 disks. We have my main macOS disk that has a EFI, Macintosh HD, Preboot, and VM partitions within disk0. Disk1 is apparently the recovery partition. Disk2 is my time machine backup drive. All of the remaining disks are very small in size, all with partitions labeled “untitled” under them. I presume that these other 18ish partitions are the remnants of partitions I created and then deleted using Disk Utility in a fully booted macOS High Sierra. All these other partitions are not visible anywhere except in recovery mode terminal. In About This Mac and normal Disk Utility it shows I have 3.78GB worth of “Other volumes” How do I delete these other 18 partitions safely? Also, what is the VM partition under my disk0 and what does it do?

I use a 13” 2015 MacBook Pro with retina running macOS High sierra 10.13.2

MacBook Pro with Retina display, macOS High Sierra (10.13.2), Early 2015 model

Posted on Jan 18, 2018 3:35 PM

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Answer 1

Capt Inc Author

Level 1

14 points

Jan 19, 2018 4:01 AM in response to Kappy

I understood what you said. I was just thinking that all these other partitions I was seeing on my Mac were the remains of partitions I created and then deleted over time. See, I made a lot of partitions all named “untitled” and then deleted them all, and seeing the command feedback in disk Utility made me think they were related.

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Answer 2

Kappy

Level 10

362,001 points

Jan 19, 2018 12:16 PM in response to Capt Inc

Why do you need to do this? Is the drive not working as is? Those items in the second pic appear normally. They do not require reformatting the drive. If you need to reformat the drive then do so using Disk Utility. Less can go wrong. Do you want to change from APFS to HFS+? If so, then do this:

Install El Capitan or Later from Scratch

If possible backup your files.

Restart the computer. Immediately at the chime hold down the CommandandRkeys until the Apple logo appears. When the Utility Menu appears:
Select Disk Utility from the Utility Menu and click on Continue button.
When Disk Utility loads select the volume (indented entry, usually Macintosh HD) from the Device list.
Click on the Erase icon in Disk Utility's main window. A panel will drop down.
Set the Format type to Mac OS Extended (Journaled.)
Click on the Apply button, then wait for the Done button to activate and click on it.
Quit Disk Utility and return to the Utility Menu.
Select Install OS X and click on the Continue button.

This will install the version of OS X you had installed.

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Answer 3

Capt Inc Author

Level 1

14 points

Jan 18, 2018 3:41 PM in response to Kappy

I assume you are talking about what the VM partition under disk0 is, right? And you are not talking about me having 21 disks?

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Answer 4

Capt Inc Author

Level 1

14 points

Jan 19, 2018 12:20 PM in response to Kappy

I guess I don't have a true real reason, but its just that I see 3.3GB as "Other volumes" in About This Mac and it seems to be a waste.

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Answer 5

Kappy

Level 10

362,001 points

Jan 18, 2018 4:08 PM in response to Capt Inc

Yes. You do have 21 snapshots that are kept in your VM volume. APFS creates four volumes:

/dev/disk8 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +199.6 GB disk8

Physical Store disk5s6

1: APFS Volume High Sierra Recovery 22.0 GB disk8s1

2: APFS Volume Preboot 25.2 MB disk8s2

3: APFS Volume Recovery 520.8 MB disk8s3

4: APFS Volume VM 2.1 GB disk8s4

The above is from my startup volume which happens not to be disk0 but disk8 on my computer. This is one partition of an external 1TB SSD that happens to be used for startup. The disk8s0 is the storage space of the container. The VM volume is 2.1GBs in which there are various of these snapshots. There is a 22GB partition that contains a bootable volume. This is not the same as the Recovery HD volume that is just under 521MBs. And, lastly, is the 25MB Preboot volume. This is the typical arrangement for an APFS volume. The actual physical store consists of slices 1 to 4. These are part of the larger SSD that has been "partitioned" into two volumes. One is an APFS volume as shown above. The other is an HFS+ volume on the same SSD, disk5. It appears as any normal HFS+ volume would appear except that it also contains the Physical Store of the APFS volume on disk5s6.

I hope I haven't made this too complicated. I'm no expert at this so I am relating what I have learned from others.

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Answer 6

Kappy

Level 10

362,001 points

Jan 19, 2018 12:30 PM in response to Capt Inc

These snapshots may be caused by Time Machine to enable Time Machine to work with an APFS drive. I'd love to explain it more but I don't really understand it all. See the Snapshots section of this article where it is far better explained than I can do: Taking Stock- Using APFS in High Sierra 10.13.1.

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