Hey guys, i did a little searching but i cannot find anything specific, if you guy can point in to a thread that answers this that would be awesome i have a late 2013 macbook pro retina 15 with the 750m anyways, i cannot unlock the little lock in the security & privacy tab. when i press the little lock to unlock it, i am asked to input my password (i don't have one so i just press enter) after that it will unlock and then immediately lock itself again. anyone know what to do? also the graphics are awful when using the integrated card. i mean when i press the mission control button, its so choppy. thank for the help guys.