I teach High School students in media and because of this it is absolutely essential that I can use a projector with my mac via a dongle from Thunderbolt to VGA. Now I am thinking about upgrading to 10.8 but one of my colleagues just updated and now she is having problems because most of the time the external display only shows a blue screen. Is this a general problem with 10.8 and if so is it fixed in 10.8.2? 