You can check the home page setting: *Tools > Options > General > Startup: Home page Firefox supports multiple home pages separated by '|' (pipe) symbols. *https://support.mozilla.org/kb/How+to+set+the+home+page 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