Are you using Windows? Do you have the setting in my screenshot below?

C'mon back, and we'll talk.

Yes.....i have it work but i get the notification when i am watching fullscreen video or in a game.......when i use the system notifications i don't but the sound event that thunderbird uses is the generic notification alert and not the new email alert like outlook uses.......

Do you have this settings panel?

Yes....and like i said....i changed the new email notification to a quack sound but tunderbird is not using that event for a new email.......it is using the generic 'notification' event.....if you scroll up in that menu you sent me it is there

Please try picking a sound from the many available in C:\Windows\Media. When you find one you like, enter it in the Thunderbird settings at the setting in the screenshot below. When you have browsed to Windows\Media and found a sound (double-click the file name to play it) you like, enter it into the blank, and Thunderbird will use ONLY that sound from that moment forward.

You're lucky you have a quack. I've never found one that I like.

Ok....you are not understanding the issue,

system notifications: -blocked when in game and full screen video -doesn't use new email event....so i have to change all events using the generic notification

thunderbird notification: -can use any sound -not blocked when in game or full screen video

I am sorry I have failed to understand the issue.

Unfortunately, there is no way (currently) to make Thunderbird NOT play the selected sound during games and full screen videos.

Have a look at this information:

https://www.thewindowsclub.com/how-to-disable-notifications-during-presentations-or-while-playing-games-in-windows-10