Intermittent "plink" HD sound - very soft

Any idea what this is??

1. It's barely audible except when there is no ambient noise (like at night).
2. It's very random and intermittent: Sometimes about 10 seconds apart, other times a couple of minutes apart, sometimes it goes away.
3. It has just recently started on this MacBook which is about 2 months old.
4. It is not accompanied by any whirring or other HD noises.
5. Usually happens during very little activity (internet browsing, relatively idle during MS Word, etc).
6. I don't think I have downloaded any firmware updates recently.

I guess I would compare the sound to a minute hand moving on a watch, kind of a little "pluk" but a very tiny sound. It's not loud but it worries me because it sounds like the hard drive, right side of the keyboard, and it can also become pretty annoying when it's quiet.

Cause for HD concern? Ideas? Explanations?

It's the hard drive recalibrating. Mine does it too, it's perfectly normal.

thats good to know my mbp does it too and ive been wondering about it

My new Aluminum MacBook is doing this too and it's not normal. My MacBook Pro never does this! It is VERY annoying when working in a quiet environment. I have searched everywhere for a solution and cant find one. Anyone got suggestions?

Back up your HDD and get a new one?

I've decided to upgrade to a 250G HD and see what happens. I bought a Seagate Momentus 7200.3 250G from Tiger Direct. If it does it with this one I'll know it's not the Hard Drive but a software/firmware/Leopard type problem with excessive parking of the heads. I wonder how many people have this happening and think it's "normal" and don't report it?

harddrive "parking"

if you do a google search,there are lots of mentions about this on other boards. Some have stated that is due to the temp of the drive. However, I have noticed it hot or cold. It parks at a 10 second interval and never ends! It is annoying to say the least. Usually, a restart fixes it. A few times, I needed to repair my start up disk, but it did not seem to correlate to the issue. No one has mentioned drive failure in the posts that I read, but I can't imagine that the drive was designed to recalibrate on random days, for a continuous cycle of 10 sec intervals. None of my other mac laptops do it either, just my 17' macbook pro 2008. If you find anything out, let me know!

HDDs can make a lot of different noises and there are a few different types of plunks and knocks. However, and noise that "develops" or was not always there, is not going to be a good noise and you should replace it right away.

Some of the noises a HDD will make are,

Calibration plunks as mentioned. A lot of people will never hear these because they are so faint.

Park Clunks, These are usually a very sharp and rapid metal clunk sound. This is the drive going to sleep and parking the heads. They arm that the heads are attached to is pulled into an electro magnet and held in place to prevent damage to the disks when the drive is moved.

And the dreaded Head Clunk. This is usually similar to the Park Clunk, but it keeps happening over and over, usually like a scratched Record. You guys do know what Records were right? This is caused by the heads making contact witht he surface of the platters of your drive. This is death. This is back up what you can NOW and buy a new drive. Not tomorrow, but NOW.

There are many others, but those 3 are the most common noises that get reported to me by clients.

Hope this helps.

thanks for the help!

thanks for the warning. I think I will be calling apple this week. I have not had java functioning, so I will be calling them anyway. It is definitely a "parking" noise, and not just a subtle click. Strangely, it has not done it in two weeks... I imagine that apple will need to replicate the problem...argh!