I'm not an expert user Orbiter, but maybe I can help.
Could you attach the Orbiter.log? It is a useful file registration Orbiter can help find problems. There all the events that happen during the simulation is written, and may indicate the cause of the problem.
Greetings and hope you get the solution:thumbup:.
|NOTE: Orbiter.log file is in the folder of your installation of Orbiter.|