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 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.When using the reset 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.When using the reset feature, your bookmarks, browsing history, passwords, cookies and web form auto-fill information will be saved. However, your extensions and themes will be removed; open tabs, windows and tab groups will not be saved; and your preferences will be reset. Learn more.
  1. At the top of the Firefox window, click the Help menu and select Troubleshooting Information.At the top of the Firefox window, click the Firefox button, go over to the Help sub-menu and select Troubleshooting Information.On the menu bar, click the Help menu and select Troubleshooting Information.
    Reset Firefox 1 - WinXP Troubleshooting info - win Troubleshooting info - mac Troubleshooting info - lin
    If you're unable to access the Help menu, type about:support in your address bar to bring up the Troubleshooting Information page.
  2. Click the Reset Firefox button in the upper-right corner of the Troubleshooting Information page.
    Reset Firefox 2 - WinXP Reset Firefox - Win - 1 Reset Firefox - Mac - 1 Reset Firefox - Lin - 1
  3. To continue, click Reset Firefox in the confirmation window that opens.To continue, click Reset Firefox in the confirmation sheet that slides down.
  4. Firefox will close and be reset. When it's done, a window will list the information that was imported. Click Finish and Firefox will open.Firefox will close and be reset. When it's done, a window will list the information that was imported. Click Done and Firefox will open.
  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 Reset Firefox… button in the upper-right corner of the Troubleshooting Information page.
    Reset 29 Win Reset 29 Mac Reset 29 Lin
  4. To continue, click Reset Firefox in the confirmation window that opens.
  5. Firefox will close and be reset. When it's done, a window will list the information that was imported. Click Finish and Firefox will open.
  1. Click this Refresh Firefox button directly, if you are viewing this page in Firefox (it won't work if you are using a different browser). You will also find a Refresh button on the top right corner of the Firefox about:support Troubleshooting Information page.
  2. To continue, click Refresh Firefox in the confirmation window that opens.
  3. 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 Reset Firefox button in the Firefox Safe Mode window, if you can't start Firefox normally.

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).