Doesn't happen every time, every so often when i alt tab out of the game and come back in all the graphics has gone black, i can see anything, i can click on stuff but only because i can see in the bottom left there is the helpful things you can do, but can't see what i am doing, can't save the game because i can't click on it, only thing i can do is alt F4 and come back in, to reload from my last save