

(I remember having the same issue of need to re-activate Windows 8.1 when that was running as Parallels "My Boot Camp". This is a work computer Naturally this is Without that, they just told me to wipe everything, re-install Win8.1, re-upgrade to Win10 and *not* remove the previous installation. The problem boiled down to proving my Win10 is really upgraded from Win8.1. And MS Activation Support left me with no solution. Windows (under Parallels) just will not self-activate. While they gave some insight as to the underlying reasons to this problem, there was no solution. I have already read through both articles you link to. I did have to activate via Microsoft phone help once under Parallels, but there was no issues. Needless to say, Windows 8.1 was fully activated on both manners of running. He said that in order to to get these files back to my machine, I would need to fully remove Windows 10, re-install a fresh Win8.1 and then do the Windows 10 upgrade again. The support person then claimed that he "cannot verify my Win 10 as an upgrade" (why would that matter?) and refused the activation help. (This file is also missing on my home computer, also upgraded from 8.1 and previous Windows removed.)

Possibly it has been removed by "Remove previous Windows installation" function - or possibly by "Disk Cleanup". He then tried to run a command that would access a file "C:\Windows\Panther\setupact.log". However, as I had removed the old Windows installation to save disk space, this directory Then they took remote connection to my machine, and looked for the "Windows.old" directory to verify the Win10 is an upgrade. They asked my Win8.1 key, which I provided. (Why would that matter? Shouldn't one be able to clean-install a previously activated Windows 10?) They were quite helpful, but needed verification that my Win10 is an upgrade and not a clean install. So, I contacted Microsoft Activation support. (Rebooting to "native" Boot Camp allows Windows to activate again. On-line activation stops with Error Code: 0xC004C003 "The activation server determined the specified product key has been blocked," The same Windows instance, when launched via Parallels 11, as "My Boot Camp", immediately reverts to non-activated. I have a Windows 10 (upgraded from 8.1 on Mac Boot Camp) which is fully activated.
