So on Thursday 13th I put down the lid of my mid 2011 Macbook Air with OS X 10.7.5 and went to go for an appointment. When I came back about 45 minutes to an hour later and opened it up again a mysterious 'click' sound effect started playing at random intervals in Google Chrome. Anyone else having this? I hadn't downloaded or updated anything either in Chrome or my notebook between going out and coming back in again. I can't for the life of me imagine where it might have suddenly come from or what it might mean, nor do I know if it's a Chrome or Mac sound - might it be a sound on Chrome that came without warning with the latest automatic update or a Mac sound that I accidentally turned on? It surely can't be the latter because I recently disabled all the alert and user interface sounds (and the volume feedback 'pop') because I didn't want them anymore, so I'm pretty baffled. I searched my machine for .aif, .aiff, .wav, .mp3 etc files that sound like the 'click' and couldn't find anything. I haven't been listening to anything on my notebook since Thursday because you never know when the 'click' will play and I find it quite annoying. FWIW (it may not be but you never know), in Chrome the only extension I have is Adblock Plus 1.7.4, and my plugins are: RealPlayer QuickTime 7.7.1 Widevine Content Decryption Module 126.96.36.1997 Chrome PDF Viewer Adobe Flash 188.8.131.52 Native Client (box unticked, I think that's by default) Java 14.9.0 Flip4Mac 184.108.40.206 Chrome Remote Desktop Viewer (box unticked, again I think by default) I also use the Spotify Web Player. Any help much appreciated - thank you!