After updaing MacOS to BigSur Parallel doesn't start

Solution option to install last 16 version doesn't work too. Installation window with dowanloading updatetes opening about 30 minutes and nothing happend. Of cource I rebooted mac befor installaton. How correct to install last version? If I'll delete current version, Windows copy will detete too?
I have installed windows 8.1 version on parallels and its very important to save this copy. If I`ll delete Parallels software, what will happen with windows 8.1? If I know in the last vesion of Parallels avaliable only windows 10.

 

Hello, are you running the latest Parallels Desktop version 16.1.1.?
You can reinstall Parallels Desktop and your Windows VM will be saved.
Also you can try to reset your VM as a possible solution and check the issue.