Since I migrated my game from XNA 4 to MonoGame some users have seen crashes that don't leave any events in the Windows log behind. Also, the normal exception handling in the game which logs and shows a dialog is apparently not working.

I'm kind of out of ideas on what to try to find out what is going wrong... the weird thing is that the crashes happen after a few minutes of gameplay.

Any ideas for how to troubleshoot this?

Actually I think there is a crash log, but the users cannot find it.
Also, I found program code that was not covered by the exception handling.