Not working since i installed mavericks, but since i don't use it, never bothered. upgraded to yosemite and same problems, googled all kinds of solutions no help. but once, only once out of random after restarting it worked, then its been same as before, not working. should i take it to apple care? I'm just hesitant because they will keep it with them for a day or some, and i cannot afford that time loss. the fact that it worked once means its some software issue? is it acceptable solution if he tells me to do a fresh install? I mean what the heck ,i'm under warranty and I don't have to format important data and settings, is it acceptable?