Phil updated his Windows 10, but it installed the enterprise version instead. Now he's getting a wrong serial number error. Leo says he could buy it, but that isn't cheap. The easiest thing to do is download the Windows Media Creation Tool and reinstall the consumer version that came with the computer. If he is going to go with Windows Pro, he can just go into the settings under System => Change Product Key and input the pro serial number after the upgrade.
Also from the chatroom - https://www.tenforums.com/tutorials/51564-downgrade-windows-10-enterprise-windows-10-pro.html