hello, firefox 19 has introduced its own integrated pdf viewer - if you want to switch back to the plugin you've used before to view pdfs just go to firefox > options > applications & scroll down and define the default action for the portable document format (pdf).

View PDF files using Firefox’s built-in viewer

I have already done this and selected "Use Adobe Acrobat NPAPI Plug-in, Version 11.0.02 (in Firefox). When I attempt to open a PDF to edit inside of Firefox, I get this message: Adobe Reader cannot show documents in this browser. We are sorry, but Adobe Reader is unable to show documents in this browser configuration.

Please use your browser to download this file and open it in Adobe Reader or Adobe Acrobat.

To avoid this message in the future, many browsers provide a way to turn off certain add-ons, and some are able to show this document natively. Please contact your browser vendor for more details.

If I click “Ok” it then renders a blank page equal the total length of what the actual PDF would be. I have selected ever other plug-in without satisfactory results and am wondering why I can’t find the “Use Adobe Reader (in Firefox)” plug-in that I seem to remember being there before. Is it possible to just download/install that plug-in. I have also already tried:

https://support.mozilla.org/en-US/kb/view-pdf-files-firefox-without-downloading-them#w_if-pdf-files-are-downloaded-instead-of-displayed-try-these-solutions

http://www.schubert-it.com/pluginpdf/

https://support.mozilla.org/en-US/kb/use-adobe-reader-plugin-view-or-download-pdf-files

What's next?

also see PDF files are blank or cause an error message on Mac - adobe's plugin a apparently doesn't work in 64bit browsers. other users have reported that it would work when you start it in 32-bit mode...

Thank you philipp, I think this is going in the right direction. The only issue now is that the "Adobe Acrobat NPAPI Plug-in, Version 11.0.02 (in Firefox)" Plug-in is no longer an option. Do you know which version of Adobe Reader is compatible with 32-bit Firefox? Hopefully I won't have to go back version by version using the trial and error method :(

You can set the pdfjs.disabled pref to true on the about:config page to disable the build-in PDF viewer.

You can check the value of the plugin.disable_full_page_plugin_for_types pref on the about:config page and remove the application/pdf part if present or reset the pref to the default.

• http://kb.mozillazine.org/about:config

for PDF files in Firefox -> Preferences I do not have the option under "Action" to select Adobe Acrobat NPAPI Plug-in, Version 11.0.02 and I don't know why because for other Adobe data and formats the option to use Adobe Acrobat NPAPI Plug-in, Version 11.0.02 is available. For "Portable Document Format (PDF) I only have the options to select are "Use PDF Browser Plugin 2.4.4" or "Use Adobe Acrobat Reader (default)". I don't know how to locate the NPAPI plugin to force it to appear on the list under "Action". Conversely, for the other three Adobe formats NPAPI is on the list and Plugin 2.4.4. is not. Bizarre! I'm new to the MAC OS so I don't know how to go deep into configuring anything complex especially since the UI hides the detailed file lists. So essentially, when I select a PDF within Firefox the 2.4.4. plug in opens in an new tab with "PDF Download by Nitro". I even tried to tell that plugin to use NPAPI but it isn't working (within it I set the preference and it isn't working).

Safari, of course, does exactly what it should with PDFs.

I also don't know how to uninstall all the apps or plugins or extensions, I only know how to disable or update them. So if I wanted to remove them all and start from scratch with just the Adobe Acrobat NPAPI Plug-in, Version 11.0.02 (in Firefox) I don't know how to do that.

Please don't make me go to the Mac Store, LOL :wink:

Christine Gilroy, CA

I did this: "You can check the value of the plugin.disable_full_page_plugin_for_types pref on the about:config page and remove the application/pdf part if present or reset the pref to the default. "

I found it and I think it worked -- I'm so happy :D

NoooOOOoooo, It shows the plug in but it's still launching the Nitro app!

How do get rid of pdfdownload powered by vuzit/NitroPDF?

I tried this:

Manually uninstalling a plugin

If you can't use an uninstaller program to remove a plugin, you can remove it manually:

   In the Location bar, type about:config and press Return.
       The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise!, to continue to the about:config page. 
   Search for the preference: plugin.expose_full_path.
   Double-click on the plugin.expose_full_path preference in the list to change the value to true.

'''''' Enter about:plugins into the Location bar to display the About Plugins page.

   Each entry in the About Plugins page will have "File name:" followed by a path. Navigate to the folder shown for the plugin you want to remove.
   Rename the file to something other than its normal name - e.g. npswf32 becomes Xnpswf32'''''''''''

   Double-click on the plugin.expose_full_path preference in the list on the about:config page to change the value back to false to avoid exposing the plugin path to websites. 

The plugin will be removed.

I can't select the file name to change it. It's just a list.

Manually uninstalling fixed this problem. My apologies for not posting sooner.