LittleJay that may not work especially if you have windows 7 on the same drive as windows 8.1 pro. I am having issue doing that with 7. I am hoping Gabe will issue another iso release or another build to the fast ring before rtm so I can do my further testing, I should of keep my older build. Upgrade really messes up either the windows 10 or 7 boot sector depending on how you restore it. So it could mess up your 8.1 pro install.