Turning off the ‘friendly HTTP error messages’ in Firefox

Get Firefox By accident I stumbled upon this Firefox somewhat equivalent of IE’s ‘Show friendly HTTP error messages’ option. Any webdeveloper should have this turned off by default. How else will you know what the problem is? So here’s how to do it:

  1. Open up a new tab (CTRL+T) or window (CTRL+N).
  2. Type in de addressbar: about:config.
  3. In the filterbar type: error and press enter.
  4. Now set the value of the ‘browser.xul.error_pages.enabled‘ to ‘true‘. Double clicking will do.
  5. Restart Firefox.

Now you’ll get extended warnings instead of the simple warning dialogs when, for example, you accidentaly link to a non-existant domain. Or, like me, the dreaded ‘The document contains no data’.

If you don’t know where to find this in IE: ‘Tools’ > ‘Internet Options…’ > ‘Advanced’-tab > Near the end of the ‘Browsing’-section. > Uncheck.

10 responses to “Turning off the ‘friendly HTTP error messages’ in Firefox”

  1. I tried this in Firefox and it has always been set to true, which is the default. However, I still get the friendly error messages.

    On another note, if I enter a URL (i.e spike), (which runs off to my localhost spike proxy), and the proxy is down, instaed it looks up on Google and sends the request to spiketv.com (or net), which is rather sad.

    Anyone know how to solve this one as well?


  2. This setting was only valid in the Fx1.0 days. When all you got was an alert box stating Firefox couldn’t do something, instead of telling exactly what went wrong. Since 1.5 it’s the other way around. Now you’ll get an error page instead of a dialog box. (Setting it to false still reverts back to the dialog.)

    If Firefox cannot resolve the address (spike) it’ll do an ‘Im feeling lucky’ on Google. That’s why you’ll end up on ‘spiketv’. To tell Firefox to look on your localhost no matter what, you’ll need to do some rerouting on your system (I assume). On Windows you’ll need to alter the HOSTS-file and tell the OS ‘spike’ is ‘’. But look that up as it’s too long a story to post here. ๐Ÿ™‚

  3. I applied the change to turn off the “friendly” messages (what could be more friendly than 404 or 500?!) and closed FF but when I tried to restart it, I was told it was already running and I had to reboot. I also still get the messages this change was meant to disable. Sigh.

  4. s says: I tried this in Firefox and it has always been set to true, which is the default. However, I still get the friendly error messages.

    Yup. Me too.

  5. You can’t imagine how many YEARS I have been looking for a solution to TURN OFF Firefox’s patronizing, aggravating so-called ‘friendly’ ‘error’ message because I CHOOSE to disallow connections to malware and adware servers using a HOSTS file, trying to hack into .jar files and xhtml files (not for the faint of heart indeed)…

    To think it was in there all along… Simply turning that value to OFF and I’m finally rid of that G*&^@%# stupid message… Now I only have a blank space where that F^$#^% ad used to be instead of being reminded that Firefox ‘for some reason’ could not connect to said ad server, LOL…

    You are a Godsend, Christopher Columbus!

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