https://arstechnica.com/gadgets/2018...y-deactivated/

For reasons that are currently unclear, Windows 10 Professional users are finding that their properly licensed installations are being deactivated.

On systems affected by the issue, Windows is complaining that a Windows 10 Home license key is being used with a Windows 10 Pro installation. To fix things, the system needs to be wiped and Windows 10 Home installed. Otherwise, a genuine Windows 10 Pro key needs to be used.