Yes, the fast release schedule is making it hard to keep all the articles up to date. Please feel free to register and make edits. I followed a link to the add-on's home page, and found these suggestions: (1) Switch Firefox 4 (hopefully works in 5) to 32-bit mode Close Firefox. Locate the Firefox program file in Finder and select it. Open its properties using File > Get Info (or Cmd + I) and check the 'Open in 32-bit mode' checkbox and close the window. Then restart Firefox. (2) Install the updated add-on from this link: http://firefox-mac-pdf.s3.amazonaws.com/fx-quartz-pdf-1.2.0.xpi Source: http://code.google.com/p/firefox-mac-pdf/wiki/Troubleshooting I have no way to test this. --- Edit: I see you already tested it. :-)