Annoying, Useless Norton "Product Message" Alert Popup

I am using NSwB. About once or twice a day, I get a popup message alert with a big red X that states: "Attention: Click here for a Norton product message." The message is unclickable (it fades on its own), goes nowhere, reports nothing, and does nothing. I am doing nothing unusual at the time (seems random), nor are there any bad consequences. It is just annoying and mystifying. How do I get rid of it?

This also happened with Norton 360 before I upgraded, I just never reported it. I am using Windows 8.1 and flip between the Modern UI and Desktop. But this Norton alert message box is clearly designed for Modern UI. It only occurs on my main desktop computer and not my tablet (Surface Pro 3). NSwB otherwise works fine on both systems.