MBP makes strange noise (left fan?)

Thanks for the video. Yes this sounds like something is pressing against the fan. I would first check to see if the attachment cable is getting caught and pressed into it. That failing I would remove the fan to see what could be pressing against it. As I always recommend, users should always use an external hard drive for Time Machine backup. These things are cheap now, under a hundred dollars and can save you a lot of greif if you ever lose your hard drive or, God forbid, your Book. Here's how to do it: Sostituzione ventola sinistra MacBook Pro Unibody 15" metà 2010