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 add-ons 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.
Note: Windows users may be familiar with a Safe Mode for Windows. Firefox Safe Mode has no connection to Windows Safe Mode.
How to start Firefox in Safe Mode
At the top of the Firefox window, click on the File menu and select Exit. Then 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 will start up with the 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 7 and Vista) and then entering the following in the text field: firefox -safe-mode
Safe Mode window
You now have three options:
- Clicking the Exit button cancels your attempt to get into Firefox's Safe Mode.
- Clicking the Continue In Safe Mode button 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 button is only enabled if you select one of the boxes above it.
Note: The following changes cannot be undone.
You can elect to make the following changes:
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, themes, and 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.
Delete all bookmarks except for backups: If you select this box and then click Make Changes and Restart then Firefox will delete your current bookmarks and replace them with the default set (This item is labeled Reset bookmarks to Firefox defaults in Firefox 3.5).
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
At the top of the Firefox window, click on the File menu and select Exit.
Start Firefox as you normally would.
If Firefox keeps starting in Safe Mode see Firefox is stuck in Safe Mode.