Are you hearing a clicking sound from your computer or an external hard drive? Clicking sounds are not good. My iMac hard drive clicked for the first month I had it. It reminded me of a miniature Irish step-dancing troupe inside the computer, dancing up a storm. Now that I have a new hard drive in it, I haven't heard the step-dancers at all. That's good, right? If only the fans were working properly...

More to the point, when talking to Apple support they acknowledged that when you hear clicking sounds, that typically means the hard drive is failing. She described it as sounding like a gerbil running around inside the computer.

To top it all off, my external Seagate hard drive has been clicking as well. It hasn't clicked a lot and it is also brand new, so I didn't worry much about it. Turns out that one shouldn't be clicking either. When I tried to re-install my iMac from my Time Machine hard drive, thankfully it did recover completely. It counts down how many minutes are left to restore from the backup, and whenever the hard drive started clicking, the minutes would increase. Clicking stops, minutes decrease. Clicking starts, minutes increase. Direct correlation between the two. I'm grateful that I could actually recover my system, but now I get to go back to Dell and complain about the hard drive they sold me, and hopefully get that replaced before I need a complete recovery and my backup fails.