Is there no way to kill a session: one user has iterrupted his session yesterday with Strg+Alt+Del and today is still in the list of connections in Navision (3.60) - twice: from yesterday and today, which is not very good for the license, he has. I just had the idea to stop and start the Navision server.
Normaly the TCP/IP closes a dead session after 2 hours (standard-value). The server should notice that the session is closed and close the Navision-session too. If that is not the case, you will have to restart the server-service.
you can define a job in your sql server to kill the idle session periodically.