I just started playing FS2004 again after a couple of years. I installed it on an external USB 2.0 hard drive with no problems, and updated it to 9.1.
When I start a flight, the exterior graphics freeze up. There's still sound, and the panel is still functional, but the graphics stay frozen at the initial view. When I try to switch views, the sound loads, but the graphics freeze. When I load the panel view again, the panel is functional, but the spot plane view is loaded.
The only thing that works is if I undock either the view or the panel. Then, everything works.
Is there a reason why this is happening?