Adobe Acrobat Update Bugs - Unable to Open PDFs in Separate Windows

There was an Adobe Update a couple of days ago and all of my PDFs are opening in the same window.  Under Preferences, in the General section, we used to be able to turn off this feature.  When I go into Preferences now, the option to turn it off is missing.  How can I stop my PDFs from opening in the same window, if the option is no longer available?