Seriously, how can there not be a found solution to this? I have looked everywhere I can think. For that last 3 weeks I had not heard it but the last 24 hours it has gone off 3 times. It make me want to throw my phone across the room. Of course that mean they win. So I won't. Other than all the suggestions before, rendering your phone uesless by turning off all your apps for extended periods, and using notification logging apps that don't do anything, is there anything anyone has found? It must be external, as the 3 chime notification sound is not saved into the phone, best I can tell.