Solved: “something went wrong” trying to create new user account on Windows 10

So, while trying to create a new user account on my Windows 10 computer, I get this:

The solution:

1. Start a command prompt as administrator.

2. Type the following command:
     net user <username> <password> /add

Voila, the user has been created. 

What in fact went wrong is that Microsoft completely broke Windows after Windows 7.