I moved a 2-year-old 1Tb Western Digital hard drive to the upper bay (over the SuperDrive) in my Mac Pro, so it's very forward in the computer and easy to hear. It makes a regular thunking noise, but when I ran TTP surface scan on it, the noise stopped. I don't know if it's heads parking, or something to worry about?

https://dl.dropboxusercontent.com/u/89241225/Hard_Drive.mp3

If you loop this mp3 in Quicktime, you will get the idea. It's not thunking as I type this.

Thanks.

You've likely already done so, but if not, back up whatever's on that HD immediately!!! Healthy HDs generally don't make unexpected noises. (Can you check that HD's S.M.A.R.T. status in Disk Utility, or, even better, with a robust 3rd party app, like TechTool Pro?)

Thanks for the speedy reply!

Disk Utility and TTP both say the hard drive is okay: SMART and surface scan. It is backed up on a nightly basis.

Did you recognize the sound? I've read that WD drives can be noisy. Certainly when data is written to it, I can hear it chattering away.

It's quiet right now...

Listen to the sounds at this site and see if anything is similar.

Sorry, but I didn't listen, because I've got absolutely no idea how QuickTime works. (I don't even know whether I'd have to use v 6 or 10.)

I've been running a WD Scorpio Blue (5,400 RPM) drive for a few years, and I've never heard any sounds from it, let alone unusual ones. (On the other hand, though, I'm not all that alert. )

I can't imagine why a surface scan would quiet down the drive; that sounds like coincidence.

(I'll guess that Jon will kick in shortly with a link to a collection of HD noises that you never want to hear. Don't know why I never bookmarked it.)

Edit: Jon on the money!

Yeah, I've listened to those sounds, especially the WD section. They all sound much more drastic than what I'm hearing from my drive. In the meantime, I've ordered a couple of Seagate 3Tb drives to replace the two 1 Tb drives that are currently installed. Amazing how much room films, music and photos can take up.

I can't imagine that a DVD burner would make any noise at all when it is idle? That is, no disc in the drive?

The only time I've ever heard a computer thunk was when it was bouncing down a flight of stairs.

Seriously, I've never heard either an optical or hard drive make a sound other than a quiet whirr, and I've never heard an inactive optical drive make any noise when at all.

Sounds like you're covered, whatever happens, so all should end well.

If I had to guess what your sound is I would say it sounds like the heads are trying to park or are parking over and over again. While you are scanning the drive the head is not going to attempt to park. Just a thought, try turning off "Put hard disks to sleep when possible" in System Preferences > Energy Saver. If that works then it is a good thing you have already ordered the new 3TB drives.

I have heard an optical drive make a somewhat similar repetitive sound when it was attempting to eject a disc and either the disc or the tray (depending on whether it was a tray or slot loader) was stuck and could not open/eject. If the sound is coming from the optical drive you could probably feel the clunks if you touched the face of the drive or tray.

It is amazing how much disk space media files — audio and/or video — can take up, I recently moved all my iTunes files to an external drive because the 1.1 TB Fusion drive in my Mac mini was filling up. It works well, but the delay loading a tune waiting for the drive to spool up after it has gone to sleep is annoying.