A likely cause of this is having your PDF reader set to something other than Adobe Reader; below are the instructions for re-setting the default PDF reader to Adobe Reader:

  1. Click the start button, then click the settings gear

  2. Click on the "Apps" item

  3. Click on the "Default apps" item:


  4. Scroll down a ways, and click "Choose default apps by file type"


  5. Scroll down to ".pdf" (the list is alphabetical), and click on whatever program is listed for it in the right-side column:


  6. In the list of options that shows up, choose "Adobe Acrobat Reader DC" (or the program with the closest name, if this doesn't match exactly):


  7. If you get a asking if you want to use Edge, select "Switch anyway":

  8. Adobe Reader will now be set as the default PDF reader. You can close the settings window.