A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Try creating a new user account in System Settings>Users & Groups. Then sign into that and see if you still have the same problem in PowerPoint. If not, there is an issue with the Office files stored in your regular user profile.
Here's how to uninstall Office for Mac. These steps need to be followed before reinstalling, or a reinstall doesn't fix anything.