When I was running in safe-mode, I saw for the first time the login-screen.
And I noticed that the username was something else then the username I use when I logon at the machine.
The username that was shown was an old username. I changed the username on the machine several years ago.
When I want to logon with my new username to the "server" on the local machine I get the message "Failed to connect to VMware vCenter Converter standalone server at localhost on port 443. Check your network connection."
I think that this could be the reason why I cannot create a machine.
Now the solution.
Last week I've updated the converter-software and this udpate remove the previous software first. So the software is installed with the recent user.