So I've had my new MBP for just over a month now and everything's been fantastic. Just yesterday though a small noise has started occurring every 20 minutes. It's not loud or anything I just don't know what it's coming from. It's not even normal times. It's like 12:11, 12:31, 12:51.... and so on. The sound is just like 3 short dings and I'm not sure what's causing this. Any ideas? Does it mean there's a problem or is there a setting I just need to turn off? I'm not even sure what caused this. It just randomly started happening yesterday. This even happens when I have nothing open so I don't think it has to do with an application or program. Any advice would be fantastic. Thanks!