How to Use Mozilla Firefox in Safe Mode

Saikat Basu 20-07-2009

ThumbnailThe Program menu of our computer lists two shortcuts for Mozilla Firefox. The first is of course the one which starts our Firefox browser. Strangely, we couldn’t care less about the second one.


What is Mozilla Firefox safe mode? Mozilla Firefox (Safe Mode) becomes the next resort when the regular browser comes crashing down. Firefox is the most talked about browser and has a fan base that would put The Beatles to shame”¦ But hey, it’s only a bunch of code so browser errors do rear their heads.

Here are 5 reasons why the Firefox Safe Mode isn’t a bad idea at all –

  1. It’s a diagnostic tool to troubleshoot issues with add-ons, themes or toolbars especially after upgrades.
  2. It can be used to compare the extension-loaded Firefox with the default clean slate version of the browser.
  3. It can be used to compare speeds if there’s a worry about performance.
  4. It can be used to pin down conflicting issues in the user settings (about:config tweakings) after an upgrade.
  5. It can be used to go back to the default installed state.

Mozilla Firefox Safe Mode gives us a window to start over (temporarily) by disabling add-ons and resetting (permanently) other settings to defaults. By comparing the performance, we can narrow down and fix the cause of any problem.

There are two ways we can start Firefox in Safe Mode (Windows) ““

  • From Start – All Programs (Programs in Vista) – Mozilla Firefox – Mozilla Firefox (Safe Mode).
  • From Start – Run – Type firefox.exe -safe-mode. Hit OK. (or “C:\Program Files\Mozilla Firefox\firefox.exe” -safe-mode)

For other operating systems, the paths are:
Linux – use Terminal and type in /path/to/firefox/firefox -safe-mode
Mac OS X – open Terminal and type in /Applications/ -safe-mode


The Safe Mode dialog box pops up.


We can choose to Exit or go for the other two options – Continue In Safe Mode or Make Changes and Restart.

Continue in Safe Mode

The browser starts in Safe Mode with all customizations disabled. Safe Mode does not load any extensions, themes and third party toolbars. Safe Mode uses the default theme. This is especially useful to check whether the problem is associated with these elements or some other hidden issues. When we exit the Safe Mode, the browser reverts back to the Normal Mode with all the customizations intact.



Make Changes and Restart

This option gets activated if we put a checkmark against any of the five options given in the dialog.


  • Disable all add-ons will start Firefox in the Normal Mode with the extensions, themes, and plug-ins disabled.  Note that they are not uninstalled, only disabled. Browse the web with the add-ons disabled or selectively enabled one by one. This helps to whittle down to the problematic add-on. After the fix, don’t forget to enable the remaining add-ons (extensions, theme and plugins).
  • Reset toolbars and controls reverts the browser to Normal Mode but without any toolbar customizations.
  • Reset bookmarks to Firefox defaults will start the browser in Normal Mode but our bookmarks will lost, replaced by Firefox’s default set.
  • Reset all user preferences to Firefox defaults will undo any changes we made to Firefox preferences and options or any through about:config.
  • Restore default search engines will revert to the default search engines of Firefox.

To exit Safe Mode, close down the browser completely. Sometimes, the browser keeps running in the background – do a Ctrl-Alt-Del to check using the Task Manager. If the browser keeps resuming in Safe Mode, close it down again and restart the computer. Then start in Normal Mode.


The first great thing about Firefox is that it is relatively non-buggy. The second good thing is that the Mozilla Firefox Safe Mode is absolutely straightforward. And the third, with Mozilla’s rich gallery of add-ons — even if one fails, there’s an alternative out there.

You might not have used the Safe Mode option frequently. Even then, your opinion matters. Do let us know your experience with resolving buggy issues.

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  1. Milander
    December 18, 2009 at 6:12 pm

    Put it like this, IE is there for the kind of people who would be happy using Apple computers, firefox is there for people who are comfortable using Windows computers... I guess that puts Opera in with linux users. Both apple and windows are fine systems, not going down that road again, but if you doN't know what you are doing windows/firefox will give you more problems because it lets you do more than apple/IE does, sorry but its true. Slapping on add-ons you'll only use once or twice is going to make it drag like a b**ch and that's where the problems are - users who don't understand what they are doing when they use the program(s) or the effect it will have on said performance. After 5 years with firefox teh only add-ons I still use regularly are stumble upon, a screen grabber, a youtube downloader and a few file converters/readers... The other add-ons aren't really add-ons such as... DivX, java, flash, shockwave...

    If you're sensible the only reason to run safe mode is number 1 from your list of 5 - to trouble shoot. Anyone who needs to use safe mode to do the other 4 shouldn't be using firefox anyway and should switch back to IE.

  2. davidbowiefanforever
    July 21, 2009 at 12:34 am

    Just wondering if there is a simple way to disable all add-ons temporarily without having to go through them one by one to disable them.

    I mean if you can do that in safe mode firefox I think we should be able to do it in regular mode as well. I sometimes wish I could disable them all with one click so I can do some things without all my add-ons interfering with the web site.

    • Saikat
      July 21, 2009 at 1:18 am

      Yes, IE has that feature.I wonder if there's an addon to manage addons in Firefox? Worth checking out.

      • davidbowiefanforever
        July 23, 2009 at 5:17 am

        If there is one for firefox. I sure don't know of one... I've looked, and come up with nothing.

  3. Muse of Rue
    July 20, 2009 at 4:17 pm

    An alternative to using Terminal to enter Safe Mode on a Mac is to hold down the "Option" key while launching Firefox.

    • Saikat
      July 21, 2009 at 1:23 am

      There's nothing similar on Windows with the Shift or Alt key combos...Thanks for the point.