Philippe, while I was experimenting yesterday with uninstalling/installing, registry checking etc. as described in my post, I did not see your reply. It’s always a good idea to listen to the developer himself… 
What lead to success was to install the driver separately after the update to 10.0.50. Now everything is up and running.
Thank you very much for your great work. For editing and mastering classical recordings, WL is the best and most complete solution I know.