My really new MacBook Air 11" has started shutting down when it has over 40% battery, and not turning back on until it's been plugged in for about twenty minutes, by which time it says the battery has about 60%. I have Best Buy protection for a year, but I'd rather not talk to them until I know more about it. Is there a way for me to test if this is a battery problem? Could it be a Mavericks bug? Thanks guys!!!