When Microsoft rolled out Windows 11/10, they offered a free upgrade to many from Windows 7 and Windows 8.1. This worked for those who had a valid license of Windows. Users in this scenario when had to reinstall Windows 11/10 again on their PC, from scratch, we’re not able to activate their copy of Windows 11/10.

The Windows Activation Error code for this scenario includes: The same error codes apply in two more cases:

You entered a product key that can’t be used to activate Windows. Enter a different product key or buy a new product key.You upgraded to Windows 11, but the activation servers were busy. If you upgraded from an activated copy of Windows 7 or Windows 8.1, your copy of Windows 11 will be automatically activated, or you can wait a while and then select Activate. If you continue to have problems with activation, contact customer support.You upgraded to Windows 11 using the free upgrade offer, but Windows 11 isn’t activated after a reinstall. Your copy of Windows 11 should automatically be activated as long as you didn’t make any significant hardware changes to your device (such as replacing the motherboard).

While you may try to run the Windows Activation Troubleshooter, the problem is tad different here. Microsoft did not have a key which you can use to activate for those who upgraded for free. If you have a Windows 7 or Windows 8.1 Key it will not work.

You upgraded to Windows 11/10 using the free upgrade offer, but Windows isn’t activated after a reinstall

The way to fix this is by sign-in with your Microsoft account. The upgrades are in association with the Microsoft account on the Windows computer.  The accounts were created either before or later the upgrade. If you had signed in with a Microsoft account, Windows Activation server will figure the association, and then activate Windows. In case you never signed in with a Microsoft Account, sadly there is no way out for you. You will have to buy a new license to Windows 10 from the Windows Store. Once you have the license, you can go to Settings > Update & Security > Activation. If you have made any significant hardware change like replacing your motherboard, but had your account connected with Microsoft prior to the change, then you can still activate your Windows. It’s getting important that you should sign-in with a Microsoft account on Windows 11/10 PC. While Microsoft kept it easy for tons of people to upgrade from Windows 7 and Windows 8.1, it’s making sure that you get a free license only when your account is connected. The best part of using a Microsoft account is that you can still use the same license after a major hardware upgrade. Let us know if it helped you resolve this Activation error.