Thanks for the help.
Does the crash suggest which component may be faulty? If it doesn't I'll just have to see but a pointer in the right direction would help a lot.

I have started yesterday playing a new save with my friend, and after a few (~2-3) hours the game crashed.
This occured just after an autosave, though I sadly didnt keep the crash log.
More problematically the game crashed again only about an hour later. The game continued to crash in shorter and ...