Have you tried this older thread solutions?
I apologize for asking a question that in all likelihood has already been asked before, but my attempts to find a previous thread with a solution to my exact situation were not yet successful. My laptop came with Windows 11 Home installed when I purchased it. Some time afterwards I purchased an...
www.elevenforum.com
1. The one that worked in your post #7 (I think you've tried this but not sure...)
2. Post #16's (that would need research or elaboration, I know myself inconcretely there's an "unattend file" that can fix problems or fulfill needs).
3. Post #17's (it seems simpler).
Do we have to learn anything new about the licenses?
Time ago I found this
Windows Activation FAQ: How do language, version, 64-bit or 32-bit, and source affect ability to install and transfer Windows licenses? when researching another thing. I learnt there that there exists, or existed, an "upgrade license" class. A license can/could be, according to the link's table, OEM, Retail, Upgrade, MSDN (likely expired?) or Volume license. Notice that an "Upgrade license" is/was essentially equal to a Retail one. This is likely why you can (or could) migrate an upgrade Windows 10 license, that came from an older Windows 7/8 one, to a different computer using a trobleshooter I cannot recall (I have never done this myself), even if the original license was OEM.
I think this procedure (as if you were changing the hw) could be appliable here. I see an upgrade from 7/8 to 10 is different from from Home to Pro, but this is a difficult problem where other orthodox solutions aren't working and they have this in common: in both cases, the activation is backed by a digital license, not by a product key.
Does 145€ cover well the steps Home->Pro and OEM->Retail? Currently Home Retail 145€ and Pro Retail 259€. The miniPC of my signature costed 310€ and it included a 10/11 OEM Pro license, I've always thought that a big part of its cost was this license.
I mean: imo the (possibly old) equalization of Upgrade and Retail licenses even if you upgrade from OEM is a simplification, but with a Store "filter" they can refine this: in the above thread post #7 solution you had to use the initial license first and then click something at the Store, instead of being recognized automaticly.
PS: now that I think about it, what if you upgrade a license and afterwards you use the
old license? Could it cause a 0xC004C003 error?
I'm also posting a possible way to get assistance from MS in the other thread. Allow some minutes please...