I have posted this in another part of the Parallels but I think that it was not the most appropriate part so I am reposting most of of it here in the hope that it gets a response. I am on Parallels 12 running Windows 10. I get this error every 4 - 5 months. I have tried all the remedies provided in various KB (eg https://kb.parallels.com/en/123150) and none of them ever work. The only "solution" that works is to uninstall Parallels, Windows 10 and any software I have installed on Windows 10, and start all over again I have now done this at least five times and enough is enough. Unless someone can provide a solution that works and stays working, I will abandon Parallels and buy a cheap Windows laptop. So far, my experience with Parallels has been one of pleasure when it is working, punctuated with total frustration when it fails and a great deal of time and effort to get back to a working model. One of the KB suggests that the problem is a failed hard drive but there are no other symptoms consistent with this, all OSX items work properly and, given the number of earlier posts by people with the same problem, I find it hard to believe that they all have failed drives. I do not mind installing and reinstalling Parallels but doing this for Windows 10 and all the Windows software on it is a great deal of time and effort. If I reinstall Parallels, can I somehow link it to Windows 10 by, for example, following the procedure set out in https://kb.parallels.com/en/123150? That is, can I resolve the problem without having to reinstall Windows 10?