I have used Acrobat reader for years. For the past few weeks when I open a pdf it asks me to subscibe to DC Pro. I have deleted from my computer and reinstalled the free version, but I still get the pop up. When I click no to the free 7-day trial the pdf automatically closes.
You can see the app name on your screen shot - it's in the menu bar. You are actually running Acrobat Pro. You need to run Acrobat Reader - find it in Applications.