Ok. So I've had my Macbook Pro for about 9 months when this really irritating buzzing, high pitched noise started coming and going. It's shrill and unbelievably annoying. Eventually it progressed to where the sound was there almost all the time (the sound is usually absent when I first start up the laptop). I tried all the little tricks that seems to work for other people in regards to noise, the magic noise killer, opening up photo booth. But none of those things worked in the slightest for me. When I adjust the screen brightness, the noise changes, but doesn't go away. I call apple care and they tell me that it's directory corruption and it'll cost $50 for him to go over it with me on the phone. Wtf? I hung up on him. I take it to the Genius bar and they tell me it's the fans. Take my computer away for 2 weeks, give it back with new fans. I bring it home and 10 minutes after I've started it up, the noise is back and with a vengeance. It sounds worse than before! I bring it back to Apple the very next day. And just my luck, the noise isn't there. Eventually after a half hour of having the laptop there, the noise kicks in. The Genius Bar dude tells me it's the fans, and it's normal. Uh, hello! It sounds like a tiny little cat is dying and screaming its head off under my keyboard. Not normal! After another hour of waiting there for the sound to get worse, the dude leans into listen and this time says that it's the inverter. Ships off my laptop to where ever and after a few days, it comes back to me with the inverter fixed. The buzzing high pitched noise isn't present at the moment (I've only had the computer on for about 20 minutes. But there's a new noise! A more constant, shrill whine. Not a buzzing sort of noise like before, but just a high pitched eeeeeeeeeeee noise that started up RIGHT from the get go. Wtf is this? It's not as bad as the buzzing, cat dying noise. But it's still really uncomfortable on the ears and pissing me off. Help. For the tl;dr people: Buzzing high pitched noise -> Genius bar -> Fans replaced -> More buzzing high pitched noise -> Genius Bar -> Ships to Apple -> Inverter replaced -> NEW whining non-buzzing noise -> Macbook Pro owner about to bash in this laptop with a hammer.