On Mac OS 10.12.6 on a new Retina iMac, after working great for a few weeks, suddenly Windows in Parallels stopped working. Beachball on startup. I had to go back to an early Snapshot of windows 10 with Parallels 13.1.1 Windows crashed and would not start. Don't know why. This has happened before. However, on getting back to an early Snapshot that finally got Windows working again, and after all the required Windows update, got it all working. Then shutdown Windows to set the Configuration Items. In particular wanted to set Sharing and Video. On all Configuration screens, unable to change anything. Not locked. see screen shot. how to resolve?