Although I like many other posters have had difficulties upgrading to Windows 10 I did eventually get around the problem by uninstalling Parallels Tools and not using the Windows update route either. Having now got everything running okay I was wondering if anyone else has experienced the very slow shut down of W10? I use an internal SSD in the Mac which as you might imagine has speeded up Parallels no end. With 8.1 both startup and shutdown were very quick. However, whilst startup is still reasonably speedy, shutdown takes ages. The spinning circle goes on and on and on, usually for well over a minute before the machine finally closes. I would be interested to hear other peoples experiences. P.S. Closing OneDrive has made the shutdown slightly quicker.