This seems to be a strange–yet common–issue with the original Macbook Air, model 1.1. This is the very first Macbook Air that Apple released, and you can tell which model I’m talking about if you have a small drop-down door with the headphone jack and USB port hidden in it. It also has vents on the bottom of the unit. This particular Macbook Air, for no rhyme or reason, will tend to just lose the sound–all sound, with no warning. Do you have this Macbook Air no sound issue? The usual cause of the issue is either a bad sound card, or, the ribbon cable that ties the sound card to the logic board. If you have this issue and you are local to Capital Mac Service, give us a call and we can probably fix you up and get you back to listening to your favorite songs in iTunes in no time!