Hello, I have a Macbook Pro mid 2009 aluminum body 2.53 ghz core 2 duo device. After recently upgrading from Mavericks to Yosemite I started hearing slight clicking noises that sounded like it was coming from the keyboard. Well I pulled the bottom cover and I can clearly hearing it coming from the Fujitsu drive in this sucker. I ran the apple diagnostics and even ran smart utility the long(11hrs) and short test and i got no errors. No crashing or lockups but I still hear it here and there. I just did a full back up on time machine. I was debating pulling the drive out and hooking up to my usb/serial cable to run Fujitsu diags on my windows box. For the love of god why are all the hard drive utilities made for only windows? As a side not which i thought was very freaky was that even when the laptop was powered off I would hear it if I moved it around. Anyhow my question was basically has anyone had a similar issue? And I was debating rolling back to an earlier OS. Could I just restore all my current data from my current time machine backup to an older OS? Thanks for reading.