I installed Monterey on my 2014 iMac. It now shows me some new volumes - there’s a system volume, startup snapshot and a data volume.
Did I install the OS on a wrong space? I think there was just one under the internal volume group before I reformatted.
Nope. What you see is normal. Macintosh HD is your read-only system drive.
Macintosh HD - Data contains your User Accounts and
Macintosh HD snapshot contains “rolling copies of a drive’s state so you can easily restore in case something goes horribly wrong”.
Disk Utility in macOS 12 Monterey Manages APFS Snapshots - TidBITS
You aren’t the only one who had questions the first time he saw this.
Thanks a lot! I was worried if I did something to the drive