Screenshot of above problem:

Try to delete the mimeTypes.rdf file in the Firefox profile folder to reset all file actions.

• http://kb.mozillazine.org/mimeTypes.rdf
• http://kb.mozillazine.org/File_types_and_download_actions#Resetting_download_actions

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

Thanks for your reply, cor-el. I tried both your suggestions and unfortunately the applications tabs is still completely blank.

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 25: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you lose personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other personal data are stored in the Firefox profile folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

I am also having this issue on both Firefox 24 and 25. I've tried all of cor-el's suggestions above, including the Clean_reinstall but the Application list is still empty. I tried rolling back to an earlier version (17) and this works fine.

Any other suggestions?

I am also having this problem with Firefox 24. As noted above, if I regress to Firefox 17, the applications appear (Tools > Options > Applications). I have tried the above suggestions with no success.

Anything new to try?

I finally found the solution. 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 verfied 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.