Issues with Microsoft Office are often resolved by doing a repair:

  1. Select the Start button image
  2. In the search box type:  Control Panel and then click to open image
  3. Click on Programs and Features
  4. Find Office 2016  (see screenshot) and select
  5. Click Change (see screenshot)
  6. Quick Repair will often do it and is quicker - but full re-install is sometimes needed - follow the prompts