I ried the installations of Big Sur in the following ways; 1.Install Catalina (latest release) and make it to beta, and install Big Sur In this case, Parallels desktop windows become black display screen and become no response. 2.By the direct install from Big Sur install app. Install and upgrade to Catalina beta comleted normally, and upgrade to Big Sur also completed. But the display windows size is only 1024x768 even I installed Parallels toolkit! Can not expand the Parallels windows! I tried the above 2 methods 2 times, but the results were the same, and so I can not install Big Sur on Parallels desktop 16! Is anyone who sucedded this installation of Big Sur, please inform me of the points to be checked and any advise.