Microsoft Outlook (Disabling desktop notifications)
Open Microsoft Outlook and click on “File” in the upper menu bar.
Next you will click on “Options” from the menu on the left.
From the Outlook Options window you will click on “Mail”.
In the Mail options you will need to make sure that there is no check mark in the box for “Display a Desktop Alert” in the Message Arrival section. If you check this box then outlook will display a notification on your windows desktop when new message arrive. When done, click the “OK” button.