w@

adding to my post aftrer more research and try/fails: It seems on Windows 10 you do not use audible manager any more. The Micrsoft store provides a desktop app. Yet this dows not help for the conversion task. I found hints to start audible manager and audible download manager in Windows 7 compatibility mode. This neither helped. I got the message: PC activated but the conversion process will find out that PC is NOT authenticated.

Alexander, I really appreciate your approach. Yet I am stuck with an exception of aax.AuthenticateWin(); hope you are still taking care of this and can provide a hint. Walt