I recently upgraded my version of Parallels Desktop to version 12 from version 11. I am running 10.12.2 on my Mac. Ever since the upgrade, I periodically have total Mac system freezes ... the entire system locks up, forcing me to reboot. PD is always running in the background, not necessarily the frontmost app. I'm wondering if there is any problem with PD12 that might cause this or any known incompatibility?