Reset Firefox preferences to troubleshoot and fix problems

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  • Revision id: 36829
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  • Creator: Jan.
  • Comment: fixed FOR version mismatch, replaced article with prefs.js
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  • Reviewed by: Ashishnamdev
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Resetting preferences (zoom, tabs, privacy, network, encryption, download actions, etc.) is one of many procedures that can be helpful in fixing Firefox issues. This has been simplified in the latest version of Firefox. Now you can restore Firefox to its factory default state while saving your essential information.

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.

  1. Click the menu button New Fx Menu and then click help Help-29 .
  2. From the Help menu choose Troubleshooting Information.
    If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
  3. Click the Refresh Firefox button in the upper-right corner of the Troubleshooting Information page.
    Refresh 35 Win Refresh 35 Mac Refresh 35 Lin
  4. To continue, click Refresh Firefox in the confirmation window that opens.
  5. Firefox will close to refresh itself. When finished, a window will list your imported information. Click Finish and Firefox will open.
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.

When troubleshooting Firefox problems, resetting preferences (zoom, tabs, privacy, network, encryption, download actions, etc.) is one of many procedures that can be helpful in pinpointing the issue. This article explains how to reset preferences by either removing the preferences files.

Warning: If changes to preference settings are not saved when you restart Firefox, see How to fix preferences that won't save.

How to reset preferences to default

Note: This will not affect any data stored in other files, such as toolbar data stored in the "localstore.rdf" file or any file-opening associations stored in the "mimeTypes.rdf" file.
  1. Exit Firefox completely (if open).
  2. Open the Firefox profile folder.
  3. Delete (or rename) the prefs.js file.
    Warning: If you find more than one prefs.js file or a "prefs.js.moztmp" file, delete these files as well and read How to fix preferences that won't save.
  4. Delete the user.js file, if found, or move it to a backup location (this file does not exist by default).