Hey everyone, I have a rather annoying problem on my MacBook. Everytime I take the power adapter out of my macbook, it shuts down. I've tried to change the settings of the power source in energy saver menu to battery, and i lock it to keep the changes. but everytime i go back it has changed back to power adapter as the power source. so annoying cause i can't use it without plugging it in.. anyone know why my settings won't lock and stay as i choose? everything else is fine its just the energy saver menu in system preferences. thanks!!!!