Pdf files do not open


I have just switched from JabRef version 2.10 to version 4.3.1 (for windows 64bits), and when I click on the pdf icon as I used to do before, nothing happens.

I’ve tried to use the new “Show document view” feature, but the Document viewer panel is empty (grey).

In preferences > External programs, I have selected AcroRd32.exe

Where does the issue come from?