Using Arc weaponry will probably make the game crash. Arrowhead has confirmed this and is working on a patch. Release window is early next week.
No Arc thrower, Arc shotgun, or Tesla tower until next patch.
… Reminds me when emoting on Vermintide 2 would crash the game…
Same for me so out of curiosity I did a “Verify game files” on Steam and it redownload 1 file and the following games ran fine. It could have been a coincidence but might be worth trying.