That same thing happened to me. There was no way to open the file and I asked someone here in the forum (Gaieus) for help. I uploaded the file, he opened it without problems and kindly sent me back a copy (with some recomendations to have a cleaner model ). I still don't know what was the cause, but you could try...

@gaieus said: Well, that card should do it (in fact, that card is a fairly good one which makes me jealous). Make sure to update the driver then. Also, under the nvidia card settings, set antialiasing and anisotropic filtering to "application controlled". I turned out that i wasn't running that card at all. The problem is now fixed and is running smoothly Thank you very much.