Reset Firefox preferences to troubleshoot and fix problems
Resetting preferences (zoom, tabs, privacy, network, encryption, updates, where to save file downloads, etc.) is one of many procedures that can be helpful in troubleshooting Firefox problems. We'll explain two ways to do this.
- If changes to preference settings are not saved when you restart Firefox, see How to fix preferences that won't save.
Solution 1: Refresh Firefox
The refresh feature restores Firefox to its default state while saving your essential information. This solution will reset preferences but will also remove other customizations, including added extensions and themes. For more information, see Refresh Firefox - reset add-ons and settings.
Solution 2: Delete Firefox preference files
Click the menu button , click and select .From the The Troubleshooting Information tab will open. menu, choose .
Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.
- Under the Application Basics section, click on A window will open that contains your profile folder.Your profile folder will open. .
Click the menu button and then click ExitQuit .
Click the Firefox menu , then click .Click the Firefox menu at the top of the screen, then click .Click the Firefox menu , then click .
- Locate and delete the file prefs.js (or rename it, for example, to prefs.jsOLD, to keep the old file as a backup). If you find more than one, a prefs.js.moztmp file or a user.js file, delete (or rename) these as well.
- You can close the profile folder and open Firefox now.