Enabling notifications in Outlook 2013 is one good way of keeping a track incoming message however; if you are t work the same feature may distract you from your work, decreasing the productivity. Nevertheless, you can disable the feature. Follow these steps.
Launch Outlook 2013 from your desktop.
When loaded, switch to the backstage view by clicking on the file option.
Next, click the ‘Options’ button to access Outlook 2013 settings.
When the Options screen appears, navigate to the Mail section.
On the right side of the window, scroll down until you find the Message arrival section. Disable the Display a Desktop Alert option.
When done, click the OK button to save the change.