I got a new 5K imac from Apple Store about two weeks ago. I opened iTunes for the first time today and found a 30-second long recording file, apparently recorded on December 24, 2015. When I played it, it had some clicking sounds (I think from mouse click or tapping) and sounded very much like someone recording to test the microphone (no voice heard but can hear a man breathing). Is this imac USED? I'm not sure where this file came from... Obviously, it was factory reseted when I received it, but is it possible that itunes files didn't get deleted somehow from the previous owner? I checked my iphone and my macbook pro many times to make sure it wasn't from icloud or something like that. Any help would be appreciated.