Unidentified Noise

I hear a 'Click' every so often on my iMac - I sounds very much like a camera shutter being released as if someone is taking a snap shot? Does anyone have any idea what this could be?

Thanks in advance for your help.

Weaselboy said:

OS X makes that camera shutter noise when you take a screen shot by hitting shift-command-4.

Click to expand...

This is exactly the sound I hear but of course I am not performing a screen shot, I could be just reading a post or I may be typing a note - makes me wonder if I have been hacked somehow and someone is taking screenshots without my knowledge.

----------

bmcgrath said:

Could be the hard drive parking.

Click to expand...

Thanks for the reply - the sound is coming through the speakers and way to often for the HD to be parking, really has me puzzled.