I've waded through the Outlook help and the Microsoft KB but can't find a way to disable this "feature." All I want is the sound notification, is it possible to stop that little envelope icon from ...

You can change notification sounds for emails and calendar events directly within the new Outlook app for Windows. In classic Outlook, you can choose whether to play a sound when a new email arrives.

Are your Outlook notifications not working at this time? This problem can be caused by a number of things so if you don’t know where to start looking for an answer, this troubleshooting guide can help ...