it happens when you open it first time after starting the game always, after that usually it happens when you open the bodies/portraits selection alternatively.. so for example :
start game -> open bodies selection *game hangs* -> open portrait selection *game hangs* -> open portrait selection again *no hang this time* -> open bodies selection *game hangs*..
also if you don't open any of the two for a few minutes it will restart so example :
start game -> open bodies selection *game hangs* -> play for 15-20 mins -> open bodies selection *game hangs*
I know this would probably not be an issue if all of these where on an SSD, but not everyone has an SSD or (in my case) free space on his/her SSD.