Adobe - PDFs Open in Acrobat, not Reader
These steps will fix an issue when Acrobat and Reader are both installed on a machine.
Open Adobe Reader
Click on start menu and find Adobe Reader. Open Reader.
Click on edit and then preferences to open the preferences setting screen.
Go to General tab
Go to General tab and scroll to the bottom. Uncheck the box that says "Always Open PDF's in Adobe Acrobat DC".
Click okay to close.
Close out of Adobe reader.
Test opening PDF
Now test opening a PDF.