Hello, Have you tried restarting Firefox in safe mode. You can do that by simply pressing and Holding on the SHIFT key and double clicking on the Firefox icon on your desktop. See [[Troubleshoot Firefox issues using Safe Mode]] --------------------------------------------------------------------------------------------------- Moreover, Your System Details List shows that you have a '''user.js '''file in the profile folder to initialize some prefs on each start of Firefox. The '''user.js''' file is only present if you or other software has created it, so normally it wouldn't be there. you can check its content with a plain text editor if you didn't create this file yourself. The user.js file is read each time you start Firefox and initializes preferences to the value specified in this file, so preferences set via user.js can only be changed temporarily for the current session. * http://kb.mozillazine.org/Preferences_not_saved You can rename or delete the prefs.js file and possible numbered prefs-##.js and user.js files to reset all prefs to the default value. * http://kb.mozillazine.org/Preferences_not_saved * http://kb.mozillazine.org/Resetting_preferences You can use this button to go to the Firefox profile folder: '''Help''' > '''Troubleshooting Information >''' Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) Note that the "Application Data" folder in XP/Win2K and the "AppData" folder in Windows Vista and Windows 7 and later versions are hidden folders. * http://kb.mozillazine.org/Show_hidden_files_and_folders * http://kb.mozillazine.org/Profile_folder_-_Firefox Please reply back to us.