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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  • Readied for localization 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 you refresh Firefox, 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 Fx89menuButton, click Help and select More Troubleshooting Information.
  2. Click Refresh Firefox… then Refresh Firefox in the confirmation window that opens. Firefox will close to refresh itself.
  3. When finished, a window will list your imported information. Click the Finish button. Firefox will open.
  4. Select whether you want Firefox to restore all or some windows and tabs and click the Let's go! button.
Note: There's a Refresh Firefox button in the Firefox Troubleshoot Mode window, if you can't start Firefox normally. You can also do a manual refresh by creating a new profile and transferring your important data to the 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).