DiskUtil questions on a "refreshed" mac

[RuntimeError]

Hi all,

Background rant: I needed a cheap mac urgently while my relatively new MacBook Pro is being repaired. Any 8Gb mac would suffice and two options seemed available: Gamble on Ebay, or gamble on Amazon's refreshed products. Amazon charges nearly three times more, but usually delivers on time, and their description stated the MacBook would be refreshed like new with a year warranty. One thing consistent about Amazon is it rarely tells the truth. The mac arrived dirty with various coloured crumbs of dusts, the keys do not sit flat so probably third party, there are scuffs on sides of the case, it rattles as though a screw is loose inside, and they have used a strong glue to stick down what looks like white protective plastic film on top and bottom. They didn't even wipe the case before sticking the plastic on so there are random bumps of crumbs sticking through the plastic! The charger is 3rd party, and to me the screen looks 3rd party too. Urgh. I thought I should check the HDD..

DiskUtility: Volume count 5: 2x APFS volumes. 1x VM. 2x not mounted. (Screenshot attached).

ADFS macHDD where I see Applications, Library, System, Users - everything really.
ADFS volume is macHDD - Data. What is this? It does not seem to be browsable in Finder.
VM. I'm guess this is virtual memory.
Two unmounted volumes. What are these please?

Thanks!

 

[Nermal]

Did you name it macHD or did it come like that? That's not the default name ("Macintosh HD" is).

ADFS volume is macHDD - Data. What is this? It does not seem to be browsable in Finder.

That's normal, since OS 11 I think. Any files you create or modify are transparently saved to the Data volume, so that the main system volume remains untouched. When you do "Erase All Content and Settings" it'll wipe the Data volume, resulting in a 'clean' system. I have no idea what happens to the other volumes when you do this though.

 

[NoBoMac]

The unmounted volumes are the Recovery volume. And the OS volume! What happens with the OS is that a snapshot of it is created and the system runs off that.

In following example, #3 and #5 are not mounted, while "OS" is #6.

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +250.7 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume ⁨Macintosh HD - Data⁩     71.4 GB    disk1s1
   2:                APFS Volume ⁨Preboot⁩                 769.9 MB   disk1s2
   3:                APFS Volume ⁨Recovery⁩                1.1 GB     disk1s3
   4:                APFS Volume ⁨VM⁩                      2.1 GB     disk1s4
   5:                APFS Volume ⁨Macintosh HD⁩            15.2 GB    disk1s5
   6:              APFS Snapshot ⁨com.apple.os.update-...⁩ 15.2 GB    disk1s5s1

Spoiler: diskutil apfs list output

| +-> Volume disk1s3 30A2B70B-2404-471C-BAAE-78F6A0DDEAC7
| | ---------------------------------------------------
| | APFS Volume Disk (Role): disk1s3 (Recovery)
| | Name: Recovery (Case-insensitive)
| | Mount Point: Not Mounted
| | Capacity Consumed: 1110519808 B (1.1 GB)
| | Sealed: No
| | FileVault: No
| |
| +-> Volume disk1s4 F9A81D2F-4A1E-4884-8870-06F8CB50962C
| | ---------------------------------------------------
| | APFS Volume Disk (Role): disk1s4 (VM)
| | Name: VM (Case-insensitive)
| | Mount Point: /System/Volumes/VM
| | Capacity Consumed: 2148560896 B (2.1 GB)
| | Sealed: No
| | FileVault: No
| |
| +-> Volume disk1s5 0FC31E46-91DC-4B8B-B7B3-E47E91EEAD54
| ---------------------------------------------------
| APFS Volume Disk (Role): disk1s5 (System)
| Name: Macintosh HD (Case-insensitive)
| Mount Point: Not Mounted
| Capacity Consumed: 15190093824 B (15.2 GB)
| Sealed: Yes
| FileVault: Yes (Unlocked)
| Encrypted: No
| |
| Snapshot: 36F1BC40-A0B9-4DD4-827E-A3CA9DC1ECBC
| Snapshot Disk: disk1s5s1
| Snapshot Mount Point: /
| Snapshot Sealed: Yes

 

[RuntimeError]

Did you name it macHD or did it come like that? That's not the default name ("Macintosh HD" is).

It came like that. Can it be renamed without breaking stuff?

 

[Nermal]

It came like that. Can it be renamed without breaking stuff?

Yes, but I wonder about the overall state of the computer if it's not using a factory-supplied image. There could be anything installed on there...

 

[DeltaMac]

Refurbished, but not by Apple -- you have no idea what you get.
I would urge you to do a "nuke'n pave" (Ignore what is on the drive, boot to an installer, erase the drive (not just the macHD volume, but erase the device, clearing all partitions). You can name the drive whatever you like. Install macOS, which will make a new set of volumes on the APFS container. One of those volumes will have the Data added to the name (don't try to add that Data name yourself, let the installer do that!)

 

[joevt]

That's normal, since OS 11 I think. Any files you create or modify are transparently saved to the Data volume, so that the main system volume remains untouched. When you do "Erase All Content and Settings" it'll wipe the Data volume, resulting in a 'clean' system. I have no idea what happens to the other volumes when you do this though.

Normal since macOS 10.15 Catalina. macOS 11 Big Sur added snapshots.

The way they mix Data and System or System snapshot volumes together is interesting. Here's some posts about that:
https://eclecticlight.co/2020/01/23/catalina-boot-volumes/
https://eclecticlight.co/2020/09/16/boot-volume-layout/
https://eclecticlight.co/2021/01/13/big-sur-boot-volume-layout/
https://eclecticlight.co/2021/09/07...navigating-boot-volumes-in-macos-10-15-11-12/

The volumes are identified by volume UUID and role so changing the volume names should have an effect.
After some install fails, you might end up with something like "MacHD - Data - Data". In this case, you want to check the diskutil apfs list and/or diskutil info -all output to verify which volumes are paired as a volume group (a data role and system role volumes) and which volumes have each role (data, vm, recovery, preboot, system). Then you can decide if the names are correctly matching ("Mac HD - Data" for the data role, and "Mac HD" for the system role and snapshots). I think you can rename a volume in the Finder and the corresponding data role volume will be renamed appropriately?