Hello. My MacBook Air keeps saying to me "Your mac is on reserve battery power" (or something like that) regardless of whether it's plugged in or on battery power with loads left. Very confused. There doesn't seem to be any pattern (ie every 2 hours) - it just does it when it feels like. Have tried a reboot - no change. The only way I've found of stopping it is muting the whole mac - which isn't a complete solution, especially if I want to listen to music or watch a video. Any help would be really appreciated, because it's driving me MAD! Thanks.