Completing Installation Issue

[SJL]

I downloaded 15, ran the installer, and my Mac restarted to complete the installation process. However, it keeps telling me to restart the mac to finish the process. I have done so three times and finally quit. I did not see any threads on this issue. Any ideas what to do? TIA.

 

[GraemeR1]

Interestingly, I also have VirtualBox installed but did not uninstall it.

 

[GraemeR1]

I had the same problem with Big Sur Beta 4 and Parallels 16. I tried all the suggestions except reinstalling MacOS and installing Parallels from the App Store. I had also deleted my Windows 10 VM to make room for Big Sur (was happy to recreate using Parallels). Used touch at terminal to create a dummy PVM file in case that helped but it didn't seem to.
What eventually worked for me was running this in terminal:

prlsrvctl shutdown

after a reboot and before starting Parallels Desktop.
This was after several attempts of sudo kextcache --clear-staging with reboots in between.
Parallels now happily running the Windows Installer.

OK, so now I have to run the above Parallels CLI command every time before I run Parallels Desktop. Otherwise, the loop dialog situation reoccurs.

 

[JonasV4]

I got the thing to run on Big Sur beta 5. Looks like there's a conflict when you have VirtualBox installed as well. I uninstalled VBox and then cleared the kexts like suggested in the first post. Then I ran parallels, did a Restart, and the VMs started loading up. Now just to get the network working...