To delete a category of contacts (not a distribution list):

1. View [menu]
2. Arrange By [pull-down menu]
3. Categories [side menu]
4. Right click a category
5. Collapse all groups [pop-up menu]
6. The number in each category will be shown in parentheses to the right of the Category Name.
7. Right click a category
8. Delete [pop-up menu]
9. This will delete every contact in that Category Name.
10. Note: If you have contacts who are in multiple Categories but one contact entry, that contact will be deleted completely from Outlook.