APFS Drives

macOS began separating the macOS system & data into separate APFS volumes back in macOS 10.15 Catalina. Unfortunately macOS still has not figured out how to allow the user to properly rename these two volumes as a set. In fact users must be careful to make sure they don't remove the " - Data" part of the volume name from the volume which uses it.

If you want to make the names match, then use Disk Utility to change the name...you must right-click or control-click on the volume in the left pane of Disk Utility to access the "rename" feature for the "Data" volume (rename only the part before " - Data"). At one time macOS 10.15 Disk Utility did modify both volumes when renaming this way, but broke it with macOS 11+.

Here is an Apple article regarding the change in drive layouts beginning with macOS 10.15+:

Apple Article: About the read-only system… - Apple Community

Apple made other drive/volume related security changes to macOS 11.x+ and the drive layout changed again for Apple Silicon Macs (most of it is hidden from users except when using the command line).

Unless you are booting more than one version of macOS on a computer, then you should just leave the volume name as the default as @leroydouglas mentioned. If you will be using more than one OS on the computer, then it is best to give it the name you want when using Disk Utility to erase the drive for the new OS.

Naming the volume with the current OS is not an ideal option with macOS these days with the broken renaming feature. As you have discovered upgrading to a new OS makes the old volume name inappropriate and it also leaves confusion in the wake when the names do not match up like you expected.

Old Art wrote:

Hi Leroy

OK. here is the Terminal list

Note the name of the first volume, Big Sur - Data , that appeared after the upgrade.

I would expect Ventura - Data, ie naming both parts Ventura and Ventura - Data. Any significance??

I am not a fan of renaming the default Volume names, if this is something you did in the past...

The default typically are: "McIntosh HD" and "Macintosh HD - Data"

I suspect it just confused the installer with custom names.

if everything is function as expected— I see no issue.

the left over remant

< 7: APFS Volume Old Big Sur 2.1 MB disk1s7 > that seems an artifact .

You can remove that old Volume without penalty, it is basically empty w/ only 2.1 MB,

ref: Add, delete, or erase APFS volumes in Disk Utility on Mac

you can see this from a pristine install (for example only)

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 314.6 MB disk0s1

2: Apple_APFS Container disk1 1.0 TB disk0s2

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +1.0 TB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 9.1 GB disk1s1

2: APFS Snapshot com.apple.os.update-... 9.1 GB disk1s1s1

3: APFS Volume Macintosh HD - Data 372.4 GB disk1s2

4: APFS Volume Preboot 1.9 GB disk1s3

5: APFS Volume Recovery 1.1 GB disk1s4

6: APFS Volume VM 3.2 GB disk1s5

Old Art wrote:

Good Day

I have a 27” retina refurb intel 2019 iMac running Ventura 13.3.1

I’m confused ( happens often)

When I was running Big Sur, I had two drives showing on my screen, Big Sur & Big Sur- Data

After upgrading to Ventura, I have a Ventura drive (with hidden Big Sur - Data included, no visible distinction) 

and a separate drive (renamed) Old Big Sur.

Examined Old Big Sur;  Capacity 499.96 GB, Available 126.11 GB (5.2 purgeable), Used 1,974,272 bytes (2 MB on Disk

I installed one small file as a test - 903 Kb. No other files visible!

The numbers don’t fit!

Question:

As I have a hidden Big Sur-Data in Ventura, Why do I have another Data drive and can I delete Old Big Sur?

and how to safely save it until I’m sure it is redundant? I can mount it, but it reappears if I reboot.

I would greatly appreciate any help, APFS has me completely lost.

So you upgraded from macOS Big Sur to macOS Ventura on your internal iMAc drive.

You can see the big picture from the Terminal.app copy and paste:

diskutil list internal

copy and paste the that output here