My microsoft account lost my activation key

Question

My microsoft account lost my activation key

Vincent Aubray 0

Today I had to reinstall windows 11 professional, which was activated and linked to my microsoft account. However microsoft somehow decided it was a different machine and somehow now it is impossible for me to activate it with the activation key I already had. So now I am stuck and I need help.

I have tried the troubleshooting options already.

Vincent Aubray 0 Reputation points

2026-11-03T07:52:33.0733333+00:00

Im switching to linux in the meantime.

1 answer

Your answer

Vincent Aubray 0 Reputation points

2026-11-03T07:52:33.0733333+00:00

Im switching to linux in the meantime.

Answer 1

DaveM121 946.5K Independent Advisor

1

Where did you get your Windows licence was that pre-installed on the PC or did you purchase a full retail Windows licence from Microsoft or from a 3rd party retailer?

Or is your Windows licence based on a free upgrade from a previous Windows 7 or 8 licence?

2

If you have your product key, download the free ShowKeyPlus app from the Microsoft Store.

On the left of that app, click 'Check Edition', then enter your product key into that app.

Please provide a screenshot of that app window and please hide your product key in the screenshot.

Vincent Aubray 0 Reputation points

2026-11-03T18:31:11.3133333+00:00

My windows license is a windows 7 professional activation key that I got ages ago, I do not remember from where. It has since then been upgraded to windows 10, and later to windows 11. The key is now registered to a device that is the one I was trying to reinstall windows 11 pro. Somehow my microsoft account believes it is a different device.

As of now, further actions are mostly impossible on my end since everything has been formatted several times and I lost just about everything. However I think I am done with windows. So unless you can solve the issue easily, further actions are not necessary anymore.
DaveM121 946.5K Reputation points Independent Advisor

2026-11-03T18:38:04+00:00

Thank you for that information.

If your Windows licence is based on a previous free upgrade form a Windows licence, that is causing the activation problem, because a while ago they changed the rules and it is not longer possible to reactivate Windows 10 or 11 with a licence based on a previous Windows 7 or 8 licence on new hardware, and even though you have not changed your hardware, that is the cause of the problem, they have blocked that on the activation servers.

This forum is just a user to user forum, the only hope you may have is to try to find a method to contact Microsoft Support and ask them to reactivate your licence for you.