First off can you confirm you have tried to follow these instructions

• Use Adobe Reader to view PDF files in Firefox
  • also note
    View PDF files using Firefox’s built-in viewer
    Applications panel - Set how Firefox handles different types of files

When I go to Options>Applications whether to turn off the default pdf viewer or set Adobe Reader as the default there is nothing within the application list. It is completely empty.

I can confirm that Adobe Reader is installed and functioning correctly outside of Firefox.

Yes I can see from More System Details aside that you do have the Adobe Reader plugin installed, so it would be expected to come up as an option.

As you have already deleted profile files I would have hoped that was not a problem, but let's double-check by using a slightly different procedure. Follow the stages and steps in the order written, stopping to test between the major resets, and then finally after the Adobe reinstall.

First stage. The file that stores those settings can be reset. Use the Trouble Shooting Information Page to open the profile folder find the file mimetypes.rdf mimeTypes.rdf and rename it.

1. Navigate to the Troubleshooting Information Page. One way to do that is to enter about:support into the addressbar there is then an option to open the profile folder.
   see Profiles - Where Firefox stores your bookmarks, passwords and other user data_how-do-i-find-my-profile
2. close Firefox
3. Find the file mimetypes.rdf mimeTypes.rdf and rename it to mimetypes.rdf.old1
   (Renaming leaves open the option to reverse the change - even if only as a temporary step to compare the original settings)
4. open Firefox, it will recreate the listing.

You should now have content types in the listing, and so be able to select Adobe Reader Plugin as the action.

Second Stage. If the content type shows but the Plugin is still not showing up then the next step is to reset that see

• Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems_re-initializing-the-plugins-database

Final Stage. Consider there is a problem with the plugin or its installation so uninstall and reinstall the full Adobe application.

I hope you are now able to set up Firefox to view pdf files with the Adobe plugin.

The plugin for Adobe Acrobat is correctly showing under add-ons. I renamed the mime file, and reopened firefox but it still is not showing anything under content type.

Sorry it did not work.
I know the Adobe plugin will be displaying in your plugins list, because it was already shown as a plugin when you posted this question.

You may still need to try the second stage, and maybe even the third.

If the content type shows but the Plugin is still not showing up then the next step is to reset that see

 *  Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems_re-initializing-the-plugins-database

I went back and tried your previous steps as well as the one you just listed. I deleted the pluginreg file to reinitialize the plugin database, checked to see and the problem was not fixed. Next I uninstalled and reinstalled adobe reader. This also did not fix the problem. I then started Firefox in safe mode and the content type still is not populating.

The only other thing I can think to try is to do a clean reinstall of Firefox. In fact I nearly said that initially given that you had tried with a clean profile already. The steps we have just tried really did not do anything more than the clean profile would have achieved.

Remember when doing the clean reinstall keep the original and the new profile. Do not use any option to remove personal information. It is now program files that are being removed.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org/all and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox).
3. Delete the Firefox installation folder, which is located in one of these locations, by default: (Windows:)
   • C:\Program Files\Mozilla Firefox
   • C:\Program Files (x86)\Mozilla Firefox
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back to see if this helped you!

Thank you.

WARNING: Do not run Firefox's uninstaller or use a third party remover as part of this process, because that could permanently delete your Firefox data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be recovered unless they have been backed up to an external device!

I finally found the solution. And no, getting rid of mimetypes.rdf wasn't the solution, nor was it anything in the Firefox profile, nor in the application.

I went to about:plugins and saw that one plugin had a file type with nothing associated with it. In my case, it was an OFD document type, listed under the FoxIt Reader plugin. I uninstalled the FoxIt application, rebooted, and verified that Firefox could now display the application list. Then I reinstalled FoxIt, and verified that it was still working correctly, and that the mysterious OFD file type was no longer showing in about:plugins.

I'm not sure if this is the exact cause in all cases, but hopefully it points you in the right direction.

The poster in this particular question included full troubleshooting information and that includes a list of Plugins that does not include Foxit.

Foxit has proved troublesome previously. Some versions were blocked from Firefox.

• see https://addons.mozilla.org/en-US/firefox/blocked/
  • https://addons.mozilla.org/en-US/firefox/blocked/p250