If Microsoft Outlook will not open when you click on the icon but Word, Excel, or other Microsoft Office applications are working fine, then most likely Outlook has stopped responding.
Try the following:
1. Restart your computer
2. If that does not resolve the issue, then in the Type here to search box, type task manager and then click on the app
3. Then scroll down the list until you see Microsoft Outlook which most likely will be greyed out with a little X
Make sure Microsoft Outlook is selected and then click on End task
NOTE: If the task manager only shows a few items, click on More details at the bottom
4. Close Task Manager with the X top right
