We recently upgraded epdm from 2014 sp5 TO 2015 sp4. We're having an issue on clients with Adobe Acrobat XI installed on their machines. When they click on a .pdf file in epdm, rather than show in the Preview window, the file opens in Acrobat XI, and the Preview pane in epdm shows a "Navigation to the webpage was canceled" message. This is only with Adobe Acrobat XI.

We have several other clients that use Adobe Reader XI, Acrobat X, Acrobat 7, or Bluebeam as .pdf viewers/editors, and they don't seem to be affected by the issue. I've tried playing with various settings, internet add-ons, etc., and maybe I just haven't found the right one, or maybe there's a compatibility issue with epdm and Acrobat XI.

If anybody has any ideas or recommendations, they would be greatly appreciated.