Fixed it myself, but do not know how to delete posts :
I have a crash right after the environmental archon talks to the main m4-78 console, immediately after Vash is killed. I have looked at a YouTube video of it and the two computers are supposed to have a bit of a dialogue but this does not occur in my game. Either way, it is reproducible and at the moment something of a game breaking bug. Any solutions? Also is M4-78 EP required to finish the game if it is installed?