I love Firefox. I mean, who doesn’t? It’s cross platform, it’s stable, it’s fast, it’s free. What’s not to like?
Even in paradise, sometimes there’s potholes. Firefox thrives on the support of it’s vast extensions library, used to add functionality and features into the baseline browser. However, some of these extensions can cause it to become unstable, giving a ‘segmentation fault’ even just trying to start up. When this happens, how do you recover from it?
Firefox provides a ‘safe-mode’ startup option that prevents all extensions and plugins from loading. You can even use this mode to clear out all sorts of information in the configuration without actually starting the browser. Recently, when I had an extension cause Firefox to segfault on startup, safe mode allowed me to turn off all the extensions and then deinstall the ones that were causing the instability, all without editing files or fiddling around on the command line.
To start safe mode, simply run the browser with the ‘-safe-mode’ option:
firefox -safe-mode
Firefox will come up with a dialog box asking what you’d like to do with your session. By default, all extensions are disabled, but you can also reset the state of the browser back to the installation defaults (effectively clearing out any customizations or changes you’ve made).
In my case, I simply clicked ‘Continue in safe mode’, then went to Tools->Extensions, and disabled the extensions I suspected were the problem. Exiting Firefox and restarting it in normal mode, and voila! It came up cleanly, and I was able to continue my work.
I’m puzzled why Firefox doesn’t show this option on the command line (firefox -?), but does show it in the man pages. Because man pages have become an unreliable source of information particularly in the Linux world, I didn’t even know of -safe-mode until asking in an online chat room.
Regardless, this is a great debugging and repair tool to get your Firefox up and running again quickly and easily.
