I had a legit windows 7 pro oem install on a bootcamp partition on my mac. I upgraded that to windows 10 and it succeeded. I also use my bootcamp partition as a bootcamp virtual machine in vmware fusion and discovered that windows 10 will be activated when I am directly booted in to the partition but will not be activated while booting in vmware. From what I've been reading this is a common problem with the free upgrade activations. What I did to get around this was use the microsoft toolkit and use the ex-activator. Now I'm activated in both direct boocamp boot and in vmware fusion. I'm hoping this issue is fixed in the upcoming release of vmware fusion 8. I'm wondering if it's possible to undo the microsoft toolkit and revert back to my "free upgrade activation" without doing a clean install.