I am running Parallels under Monterey to run a High Sierra VM so I can use some 32-bit apps. I got the VM set up and High Sierra installed and running fine. Then, I ran Migration Assistant from a Time Machine backup in order to port over my apps and documents, but haven't been able to get to the High Sierra desktop since; I get to the black Apple screen with the booting progress bar, and as soon as the progress bar hits about halfway the screen flashes back to the "Parallels" pre-boot logo screen then the black Apple boot screen/progress bar starts over again.
