Just updated sierra in the hope this would fix problem in parallels, since installing sierra. Unfortunately still no change. After being away from pc for a few minutes and moving mouse on return, it freezes and becomes unresponsive along with mac wheel image, this continues for a few seconds or for minutes, depending on the time away from using pc. (Using Windows 10/Parallells 12, although I have tried windows 7 & 8 virtual machines and still see the same problem) Can anyone help please as same virtual machine worked fine on yosemite . .