Since he updated from Windows 8 Home to Windows 10 Home using his Microsoft Account he will share the SAME KEY as everyone else (who have done the same thing as him). This key specifies it only works for people with a License connected to their account. Sharing this key is not illegal nor wrong as it is common knowledge and shared globally. This resolution does not require a reinstallation. Evidence of legality:
- I upgraded several devices with different account checked the key: the same!
- I asked a Microsoft Employee: He says everyone who has upgraded share it. Therefore it is legal.
By using this key, as it is linked with their Microsoft Account, they must be logged in as they activate with this key, using an account in which they had upgraded with before.
You may have to use slui.exe (Windows Activation Client). You may use Windows Run (Win + R).
- slui.exe 3 - Enter product key
- slui.exe 4 - Activate by phone. Type in the key before hand first. Use this if activation fails
Some things you want want on hand is the OEM License Key and Product Key of Windows 8.1 or 8 if you are connected to an agent if this activation fails.
To obtain the information (do this beforehand) use the utility ProduKey.exe . You may have to deactivate some firewalls (third-party and or Windows Defender). Unlike the other utilities (as posted) this one is free and it gets the OEM keys that are inbuilt into BIOS. This may also be handy if you want to reinstall Windows 8 or 8.1 (if you want to do the entire nagging process over again from 8.1).