Reset Firefox preferences to troubleshoot and fix problems
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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
Note: When using the refresh feature, your bookmarks, browsing history, open tabs, windows, passwords, cookies and web form auto-fill information will be saved. However, your extensions and themes will be removed and your preferences will be reset. Learn more.
- Click the menu button
and then click help
.
- From the menu choose .
- If you're unable to access the menu, type about:support in your address bar to bring up the Troubleshooting Information page.
- Click the button in the upper-right corner of the Troubleshooting Information page.
-
- To continue, click in the confirmation window that opens.
- Firefox will close to refresh itself. When finished, a window will list your imported information. Click and Firefox will open.
and then click help
Note: There's also a Refresh Firefox button in the Firefox Safe Mode window, if you can't start Firefox normally. If you are unable to find the Refresh Firefox button on your version of Firefox, you can also do a manual refresh by creating a new profile. See instructions on how to create a new profile.
Solution 2: Delete Firefox preference files
Click the menu button
, click help
and select . The Troubleshooting Information tab will open.
- Under the Application Basics section, click on . A window with your profile filesfolder will open.
- Click the menu button
and then click ExitQuit
.
- 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.
Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.