How to Start Mozilla Firefox in Safe Mode

When you install the Mozilla Firefox into your system the Program menu displays two types of shortcuts of Mozilla Firefox – Mozilla Firefox (the one which we normally use to start the Firefox browser) and Mozilla Firefox Safe Mode.

Mozilla Firefox Safe Mode

Mozilla Firefox Safe Mode is same as Windows Safe Mode. In Windows OS, when most of the functions don’t work in Windows normal mode we can use the same functions in Windows Safe Mode. Similarly, when Mozilla Firefox crashes due to theme or extensions, we don’t have to install them again to resolve the crash issue; we can use Firefox in Safe Mode.
In safe mode, Firefox does not load themes, extensions, or a customized code, that’s why; it is safe. It facilitates you to temporarily (or “permanently”) disable add-ons, toolbars, bookmarks, etc… and provides user-friendly interface to troubleshoot any issue.
Let’s see what all things we can do in Safe Mode,

  • We can troubleshoot the issues related to add-ons, themes or toolbars and also we can disable them.
  • We can rearrange toolbars and controls, all user preferences to Firefox defaults, and default search engines.
  • Delete all bookmarks except backup.
  • We can go back to the default installed form and can compare speeds for performance.

How to Start Firefox in Safe Mode

In Windows OS

Using Run dialog box: Click on Start, in the “Search Programs and Files” search box type Run and press OK. The Run dialog box opens, type “firefox.exe -safe-mode” (or “C:\Program Files\Mozilla Firefox\firefox.exe” -safe-mode) and press OK.
Using Firefox Shortcut: Using this method you can run Firefox in safe mode for long term period and you don’t have to type the same command every time to open Firefox in safe mode.
To do so, open the properties dialog box by right-clicking the Firefox shortcut and in the Target text box just type “C:\Program Files\Mozilla Firefox\firefox.exe” -safe-mode.
The Firefox Safe Mode pop-up window opens. This pop-up window will ask you to Disable and Reset the elements of the Firefox and along-side displays three buttons to take action,

  • Make Changes and Restart
  • Continue in Safe Mode
  • Exit


1) Make Changes and Restart

Tick the check boxes as per your requirement and click the button. Using this option, you can play with any extension, theme, or code that might crash your Firefox browser.
Let’s see, what these check box features says,

  • Disable all add-ons: This will start Firefox in the Normal Mode with all disabled add-ons (extensions, themes, and plug-ins). After opening the browser, you can enable them one-by-one to know and fix the issue caused the browser crash. After fixing the issue, you can enable all add-ons.
  • Reset toolbars and controls: It will return the browser to Normal Mode without any toolbar customizations.
  • Reset bookmarks to Firefox defaults: It will open the browser in Normal Mode without bookmarks (replaced by Firefox’s default set).
  • Reset all user preferences to Firefox defaults: This will undo all changes that we made on Firefox preferences and options.
  • Restore default search engines: It will return the default search engines of the Firefox.

To exit the Firefox from the safe mode, close the browser by clicking cross button, but sometime, after closing the browser too, the browser runs in the background of the system. To close the browser from the background, open the task manager by pressing “Ctrl-Alt-Del” from the keyboard and end the services.
Next time, when the browser still opens in Safe Mode, close it down again and restart the system. The browser will open in Normal Mode.

2) Continue in Safe Mode

To open the browser in safe mode, click this button.
The browser will open in Safe Mode with all disabled add-ons (extensions and themes) and third party toolbars, helpful in knowing and fixing the issue caused the system crash or hang.

3) Exit

If you don’t want to open Firefox in Safe Mode use this button

In Linux

Open Terminal and type in “/path/to/firefox/firefox -safe-mode. The Safe Mode dialog box opens.

In Mac OS X

Open Terminal and type in /Applications/ -safe-mode. The Safe Mode dialog box opens.


Firefox Safe Mode is one of the special mode of the Firefox used to troubleshoot and fix problems comes in Firefox normal mode. Safe Mode temporarily disables hardware acceleration and add-ons, and resets some settings that might be crashing or hinging Firefox.

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