Safe Mode is a special Firefox execution mode that can be used to troubleshoot issues in Firefox. In Safe Mode, you can reset some settings or disable extensions and themes that might be the source of the issue. By comparing Firefox behavior in normal mode to its behavior in Safe Mode with various items disabled, you may be able to diagnose issues.

Table des matières

• How to start Firefox in Safe Mode
• Safe Mode window
• Exiting Safe Mode

How to start Firefox in Safe Mode

1. Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Exit menu item.Close down Firefox completely: On the menu bar, click the Firefox menu, and select the Quit Firefox menu item.Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Quit menu item.
2. In Windows, click Start, open the All Programs list, and navigate to the Mozilla Firefox folder. In the Mozilla Firefox folder, select Mozilla Firefox (Safe Mode).
   Firefox 3, Mac OS:

   Hold down the Option key, as you start Firefox.
   Firefox 2, Mac OS:

   Go to the Utilities directory (in the Applications folder) and open Terminal, then run:

   /Applications/Firefox.app/Contents/MacOS/firefox -safe-mode

   Go to your Terminal and run:

   /path/to/firefox/firefox -safe-mode

3. Firefox should start up with a Firefox Safe Mode dialog.
   
   Note: You can also start Firefox in Safe Mode by clicking Start, selecting Run (or use the Start Search box in Windows Vista) and then entering the following in the text field:
   

   firefox -safe-mode

Safe Mode window

You now have three options:

• Clicking the Exit cancels your attempt to get into Firefox's Safe Mode.
• Clicking the Continue In Safe Mode starts Firefox in its Safe Mode. While you are in Safe Mode, your extensions and themes will be disabled, and any toolbar customizations will be reverted back to their defaults. These changes are not permanent - when you leave Safe Mode and start Firefox up normally, your extensions, themes, and settings will return to the state they were in before you entered Safe Mode.
• The Make Changes and Restart is only enabled if you select one of the boxes above it:
  • Disable all add-ons: If you select this box and then click Make Changes and Restart then Firefox will start back up in its normal mode, except all your extensions and themes (but not plugins) will be disabled. (Not uninstalled.)
  • Reset toolbars and controls: If you select this box and then click Make Changes and Restart then Firefox will start back up in its normal mode, except any toolbar customizations you have made will be lost, such as position of buttons and toolbars,
  • Reset bookmarks to Firefox defaults: If you select this box and then click Make Changes and Restart then Firefox will delete your current bookmarks and replace them with its default set.
  • Reset all user preferences to Firefox defaults: If you select this box and then click Make Changes and Restart then any changes you have made to Firefox's options will be set back to their default settings.
  • Restore default search engines: If you select this box and then click Make Changes and Restart then any of the default search engines you deleted will be restored.

Exiting Safe Mode

1. From the menu at the top of the Firefox windowbar, select FileFirefox and then select the ExitQuit FirefoxQuit menu item.
2. Start Firefox as you normally would.
   • If Firefox keeps starting in Safe Mode see Firefox is stuck in Safe Mode.

Based on information from Safe mode (mozillaZine KB)