whew.. so I lost an entire day to this.. I was testing my project and realised that if I stay on one frame for >3 minutes and then try to load another frame, the game will hang. I spent hours pouring through my map loading code (fast loops etc are usually the culprit) I slowly pulled the project apart bit by by until I was only left with the Joystick 2 object sitting in the frame (no events related to it)
So I found that if you have a Joystick 2 Object in your frame and leave that frame running for >3 minutes, then jump to another frame, Fusion will crash..
I'm posting this here to see if others can re-create the problem - annoyingly you'll have to wait 3 minutes for the bug to happen.... but it's a small price... I waited 3 minutes every time I was trying to narrow this problem down (probably 300 minutes in total) Attached is an example to make it easy.
In the end I did find a way to stop the crash from happening, I unchecked all the boxes in the Joystick 2 settings, I suspect it is something to do with either the polling on syncing with Fusion and maybe something to do with newer versions of windows from Vista onward.
It seems I can carry on with my project because it's all working without those settings checked.. but Joystick 2 is an important extension, so if it has a major bug like this I think it's best to get it fixed.