I have the same problem. It started happening after the windows 10 April update. It was so bad that I could not do anything because it would freeze 10 second after the startup. After *a lot* of attempts stopping it and starting it I managed to install the parallel tools and it was a bit more manageable. I tried to reinstall completely windows but still I have the same problem. I already disabled the fast startup and it doesn't help. Also in my case it happens when I'm using Visual Studio 2017, but it's pretty much the only thing that I do in parallels. The last time that it happened I had the audio open and I noticed that the speakers started doing an awful "ding-ding-ding-ding" noise while it was frozen. In the event viewer there is pretty much nothing strange. I think that in my case it happens more frequently after I resume a suspended VM. Let me know if you need anything that can help from me.