I have a the iMac 27" 2010 with whatever the last update was. After that update, \nI get white screen with loading bar then\nBlack screen with mouse icon parked in the upper left corner only then\nMouse disappears. Hard drive sound is it's working.\n\nAlready tried to start in restore mode planning to use timemachine on airport, but it won't populate, so no luck.\nTried safe mode. Aftrrer white screen it goes back to the black screen and hangs, so no luck either.\nTried to reset SMC & PRAM. no change.\n\nAny help? I'm desperate.