Install this add-on

In order to change the default reader for PDF files (to not open PDF files with Firefox's internal PDF reader), follow these steps:

1. Go to Tools > Options (or Firefox > Options).
2. In the Options window, select the Applications tab.
3. In the Search field, type PDF. You should find Portable Document Format (PDF).
4. On the right handside you should find an Action column. Use that to select your favorite PDF reader. In order to view PDF files in Firefox, choose Preview in Firefox.

I hope this help.

I currently have "use adobe acrobat" for the PDF and the adobe acrobat forms (all three) options. This is what should happen (open in a new window) and does in IE.

What you also could try is to disable Firefox's built in PDF viewer or to disable the plug-ins. Start with one and then do the opposite.

-To disable Firefox's built in PDF viewer you type in "about:config" in the URL line, hit enter. Search for "pdfjs.disabled", double-click it to change it's value from False to True. Now try to open the PDF file.

If this doesn't work, enable the built in viewer and disable the plug-in.

-To disable the PDF-plugin go to Tools > Addons > Plugins and hit Disable to the right of the PDF line.

Of course both of these methods should work, but this might give us some clues to your problem.

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

You can also check the value of the plugin.disable_full_page_plugin_for_types pref and remove application/pdf.

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

Thanks for the help. It didn't work, unfortunately.

I can't believe it is this hard to open a PDF in Firefox.

It was cool to find out about "about:config" however.

You can change the action for Portable Document Format (PDF) from Preview in Firefox to use the Adobe Reader or set to Always Ask in "Firefox > Options/Preferences > Applications".

• https://support.mozilla.org/kb/change-firefox-behavior-when-open-file

I've tried:

Updating FF Updating Adobe reader Updating Adobe player

Plugin Adobe Acrobat 10.1.16.1 (both enabled and disabled) Plugin Adobe Acrobat 11.0.2.0 (both enabled and disabled)

Extension PDF Viewer 0.7.236 Extension Adobe Acrobat - Create PDF 1.2 (both enabled/disabled)

pdfjs.disabled/enabled

Tools | Options | Applications: Adobe Acrobat Forms Document Use Adobe Acrobat (default) Adobe Acrobat Forms Document Use Adobe Acrobat (default) Adobe Acrobat XML Data Package Use Adobe Acorbat (default) Portable Document Format (PDF) Use Adobe Acrobat (default)

Did you trying swaping the Tools > Options > Application > Use Adobe Acrobat (default) to Use Adobe Acrobat (Firefox) ? Just a thought..

Just tried it. No luck. I can't imagine what configuration I must have that prevents opening a PDF from Firefox must be. Especially when the darn IE works perfectly in this instance.

I just had this problem as well. I too was able to open PDF's using IE8 but when I tried to view the same document in FF it seemed to open Adobe, or something like it, but all I got was a blank sheet with a " I'm busy doing something" indicator in the middle of the sheet. I tried a number of the so-called fixes/suggestions I found under this forum string and got NOWHERE! So I uninstalled Firefox, but kept my personal data and such. Upon reinstalling FF I can now open the PDF file that was a problem. Coincidentally it appears the FF is now running much faster than it had in the past. All of this is just an FYI  !!!!!