Pretty much, we have the conversation and as the chat box goes away to zoom out it freezes. This has happened 20+ times in a row so at this point I'm giving up for awhile and hoping the next patch might help... but, my last save game is 4 hours prior, one of my savegames are right when I enter the brotherhood's hideout but the door locks right when you enter so that save is useless..

I am not sure if you sided with Hardin or not, but I know siding with Hardin can cause the game to get stuck in a loop where neither Hardin or McNamara will talk to you. I had to lose 10hrs of game play to go back and side with McNamara and the quest worked fine.