I was in the desert and my jeep bounced back from an invisible area. I got out and tried to run past the barrier and fell out of the map. Now game wont start, it stays on the loading screen. Not sure if it matters but I play offline.
That is probably caused by a corrupted save or region file. You could check your region files in your save folder for that map/save and see if any are 0 bytes. If so, you can delete it and see if that works.