When I go to actions, all the options are greyed out except 'Start', while the Windows 10 "Checking the disks..." message has been sat there with the spinning wheel for the last 5 or more hours.I had a similar problem. Parallels would start but Windows would be stuck at the spinning wheel, which happened for days (I'd leave it running in the background all day but it still wouldn't boot). I have just been able to get Windows to start by going to Actions-->Reset. I ignored the warning message and canceled disk checking (Windows prompted me to press any key if I wanted to cancel disk checking), Windows went on to install a few updates, and my VM booted up okay. It's now running smoothly.