Steps to make Acrobat Reader DC or Acrobat DC your default PDF program:
   

    • Right-click the thumbnail of a PDF file, and then choose Properties.

      Right-click and click Properties

    • In the file's Properties dialog box, click Change.

      Click Change
      Note:

      If your computer settings are managed by a system administrator, you may not see the Change button. Sign in using an administrator account or contact your administrator to get the button enabled.

    • Do one of the following:

      If you have Acrobat DC or both Acrobat DC and Acrobat Reader DC, choose Adobe Acrobat DC and click OK.

      Choose Acrobat DC

      If you have only Acrobat Reader DC, choose Adobe Acrobat Reader DC and click OK.

      Choose Acrobat DC

    • In the Properties dialog box, click OK.

      Click OK in the Properties dialog box

      Now, the PDF files open in Acrobat Reader DC or Acrobat DC.