If you are unable to see new messages coming up in your Unread Mail folder, it might be because you have a filter set up. Here's how to check!
1. Open Outlook.
2. Click on the View heading.
3. Click on View Settings.
4. In the Advanced View Settings window, click on the Filter button. In this example, there are not any filters in place, so that is why it indicates that the filter is off.
5. If you have any filters in place, click on the Clear All button, then the OK button. You will be brought back to the Advanced View Settings window. Press the OK button to get out of the window.
6. Now you should see the number of emails populating the Unread Mail folder.