Today I was installing Quickbooks on a Windows 10 Pro computer and needed to open a Portable Document File (PDF) during the installation. This windows 10 computer was recently wiped and reloaded so it didn’t have many programs available. It did have Mozilla Firefox which is a web browser I installed in addition to the Edge web browser. When the PDF was clicked-on, Windows didn’t know what program to use and prompted me to select one. I looked through the list and had a hunch Firefox might be able to do it because I’ve seen Internet Explorer do it in the past. I was right and it opened the file just like Acrobat or Foxit PDF Reader!