The other solutions didn't work for me, but it's actually really easy to fix, Apple Support (phone) was incredible, call them if this doesn't work for you: My issue was that I had accidentally hit "Erase" instead of "Erase Volume Group" on Macintosh HD. The "Erase Volume Group" option would have basically erased the container that contains both "Macintosh HD" and "Data" internal volumes, instead of just Macintosh HD. 1) In Disk Utility, go to View and choose ""Show all" (I believe the shortcut is CMD+2) 2) Select the disk that contains Macintosh HD and Data. In my case it was called "disk3". Erase that disk. It might warn you that you will need internet to reinstall/activate your Mac, that's fine. 3) You now need to reinstall macOS now. But in my case, I had an error at some point before that, where the Recovery Assistant opened and said "Your Mac has no volumes to recover". If you get that error, in the menu bar, tap "Recovery Assistant" and then "Erase". That's it, after that you should be able to restart your Mac (open the start options through CMR+R on Intel or long-press on power button on M1) and reinstall macOS.