I'm running Parallels 16.1.0 (48950) on a Mac Pro. I have Mojave running natively, but I also have Mojave running under Parallels with no issues. Apple doesn't seem to offer Catalina upgrades from Mojave now - the Software Update feature says I can go to Big Sur. I thought "What the heck?" I backed up the .PVM file, fired up Mojave in a Parallels VM, and tell it to upgrade to Big Sur. It downloads, restarts for the installation, and eventually comes to a desktop under Parallels. Desktop looks fine, clock display in the upper left corner of the screen updates, and in general, it looks good. But, neither the mouse or keyboard appear to be working. I've rebooted a few times, but no change. prl_disp_service seems to be using some cycles on Mojave where the VM is running, but nothing excessive. The Activity Monitor for the Parallels VM shows normal CPU activity - maybe 2 to 20 percent. Suggestions? Bug?