This problem arises because when you install a more recent version of macOS on any Mac, the macOS installer also updates its firmware, including the Recovery system. Within that, the Install macOS name of version app which performs the installation can only install that one version of macOS. Let’s say you were running Catalina, and upgrade. With the APFS file system is still easier. Within one section, you can create multiple volumes to install different operating systems. Adding and deleting a volume is much faster than partitioning a disk into several logical partitions. In addition, the volume may have a dynamic size. No need to initially calculate the amount of space required.
My mac is using Catalina, I was following the link installing macOS Beta on a separate APFS volume to install Big Sur Beta. After installation completed, I switch back to Catalina, I found the developer app installed on Catalina won't work, it crashes immediate when I open it.I tried to delete the volume that installed Big Sur Beta
, but it's not working, I am still not able to open developer app. Further more, on Catalina OS Volume, there are two new volume was created:Volume with name update appears on desktop, I have no idea what it is.
Volume with name disk1s7 appears on disk untilites, I cannot erase it, I cannot delete it.
The question is, how to completed remove beta OS from separate APFS volume with the volume update and disk1s7?