Tried playing this with a friend and alone but no matter which mission we started, the game crashes with UE4 fatal error. Verified all the files, multiplayer is installed, halo 2 is installed. Language pack is installed, game is set to english. Anticheat is off. But no matter what I do, the game crashes before the first loading screen ever starts. Any level, any difficulty.

I have the game installed on a separate disk inside the PC. Core i9-13900K, 64GB of RAM and a 7900 XTX. On Steam of course. Any idea what else I can look into to get this mod working?