Same problem. Windows boots and the desktop displays for up to 60 seconds and then the screen goes black and I'm left with only a cursor. If, as soon as the desktop is shown after logging in, I launch an application that application will stay visible, but the taskbar and desktop will soon go black. I'm running latest version of Parallels 10 (10.2.0 build 28956) and latest version of Windows 10 (build 10074)
UPDATE: Per this thread, turning off nested virtualization and PMU virtualization seems to have fixed it.
Last edited: May 11, 2015