Once in awhile i'll get what I assume is an alert on my iMac, but I don't know what it's for. This morning for example I turned on my iMac and I only had Safari open but I heard a two tone alert, but I seriously doubt that alert came from Safari. I'll hear that every once in awhile but I could never seem to figure what it's for? Do you guys have any idea where I can find out where that alert is coming from?