Running with PW SS4 .590 or PW CE .67, with Acrobat Reader 11 installed, PhotoPreview of PDF files works properly.
Once I installed Bluebeam 2015.6 - standard as a PDF editor (Acrobat Reader 11 remains on the machine), Bluebeam becomes the app for PhotoPreview and the PDF files do not preview properly.
How do I set the PhotoPreview back to Acrobat Reader?
The Photo Preview tab is simply opening the file in a web browser... so to test, right click on a pdf outside of PW and open in internet explorer. With the issues I had seen, this also did not work when Bluebeam was the default application on the machine. That is what they have fixed in the newer releases.