Windows 10: Failed Activation

Run showkey plus from this forum. It might tell you the product key that you upgraded from so you can write it down:
Showkey - Windows 10 Forums

You don't have to erase your current Windows 10 to clean install Windows 8 for the purpose of restoring the Windows 8 product key. You can make an image of the Windows 10 to external storage using something like Macrium Reflect Free (that we highly recommend), and restore it after the Windows 8 temporary install and activation. Or you can use MiniTool Partition Wizard to shrink your existing Windows 10 partition by 50gb and create a temporary partition to hold a Windows 8 install.

Likely all you are going to have to do is activate Windows 8 once on that same computer to attach the Windows 8 product key to it, but if you get Windows 8 activated on it, I would highly recommend generating and saving the genuineticket.xml file.

 

ok...I will try but i think windows lock my 8.1 key out. So i am not sure if i can reinstall 8.1. I will make an image file...thanks for suggesting that.

 

You need to blank out the original key. Remove the screenshot. Click on the key in ShowKey to XXX it out, then repost. The Win Next Starter Retail key will only be good to upgrade to Windows 10 Home - not Windows 10 Pro.

 

The Win Next Starter retail key is a generic that GWX inserted prior to the update - it was part of GA release but has been removed from v1511.

 

Interesting. So it can't be used to activate an installation of Windows 8.1 then?

 

Yup, was there since tech preview days - not sure why... particularly as it was in both Home and Pro install.wim indices.

 

Problem fixed. I had a system image of 8 .1 pro and was able to activate on from my phone. Win 10 pro upgraded just fine. Thanks to all who responded:

 

Did you run showkey plus to capture the Windows 8.1 Pro product key so you have it for future reference?

 

Yes and thanks for the mini partition app also. Where do I add to your reputation?

 

Thumbs up icon at bottom of each post. Glad it worked for you!