Me and my friend are having troubles playing certain zombies maps with each other. specifically Project Contamination and Oil Rig. He has installed t4m but when he loads in most of the models don't appear and boxes float above everyone else in the game. Anyone know how to fix?

Me and my friend are having troubles playing certain zombies maps with each other. specifically Project Contamination and Oil Rig. He has installed t4m but when he loads in most of the models don't appear and boxes float above everyone else in the game. Anyone know how to fix?

lower texture settings and turn off specular maps