Every now and then the time arises when I need some help, and this is one of those times. I just purchased a refurbished 2009 MacBook from MicroCenter with a 2 year and 90 day warranty, and it has been working flawlessly. The first time I used GarageBand on it, I did some vocal (I can't sing at all lol) recordings and all was well. The next time I used GarageBand and recorded some vocals there was a high pitched buzzing sound. I read USB mice can cause this, but I have nothing hooked up to my MacBook except the MagSafe power adapter and a BlueTooth Mighty Mouse - which I have tried disconnecting but no luck. Any ideas? I'm going to try Audacity and see if this buzzing is there too, will report back.