Some add-ons can cause this problem. In particular, try to disable or remove anything by Conduit, such as a Community Toolbar add-on. You can do that on the Add-ons page. Either:

• Windows: Ctrl+Shift+a, Mac: Command+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

You can select the category in the left column. I suggest checking both Plugins and Extensions.

If built-in search engines are missing, you can check whether they are disabled in the Options/Preferences dialog. If you click the magnifying glass icon at the left of the search bar, you can access the search settings from there.

Bookmark and use this; Download the Mozilla Search Reset {web link} This add-on is very simple: on installation, it backs up and then resets your search preferences and home page to their default values, and then uninstalls itself. This affects the search bar, URL bar searches, and the home page.

Try to delete the search.json file and possible search-metadata.json and search.sqlite files in the Firefox profile folder to reset the search engines to the default.

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

Firefox will rebuild the search.json file from the default search engines in the "browser\searchplugins" folder in the Firefox program folder and the searchplugins folder in the Firefox profile folder.

You can check for problems with preferences.

Delete possible user.js and numbered prefs-##.js files and rename (or delete) the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in the current Firefox release.

• http://kb.mozillazine.org/Preferences_not_saved
• http://kb.mozillazine.org/Resetting_preferences