After one of my computers updated to 1809 (Oct 2018) the Windows 10 edition was changed from Professional to Enterprise, this left the computers license unactivated.

To fix this issue click the ‘Change Product Key’ and paste the following Microsoft Generic/Dummy Windows 10 Professional key:

Update Product Key
Click ‘Change Product Key’ in activation settings


This will switch the edition back to Professional and in the case of my computer the license then activated from my Microsoft Account.