MAJOR Change Setting Default Preferences for Firefox 14

IMPORTANT: These locations changed again in Firefox 21. See this post.

If you are running into problems with Firefox 14 not honoring values in you set the default preferences, it’s because Firefox preference files have moved from defaults/pref to defaults/preferences and your files have to move as well. (See bug 779437.)

Apparently custom changes to the default preferences were supposed to be there all along, but no one actually knew that (not even Firefox).

So when you are creating JS files for your autoconfig settings or to set the various add-on scopes values, make sure they are in defaults/preferences. (You’ll have to create this directory.) Note that this method works fine on Firefox 10 as well. I’ll be updating all my posts as I have time.

On a separate note, the CCK is broke on Firefox 14 – it’s not creating bookmarks properly. I’ve tracked the problem down to a Places change, but at this point I am unable to work around it. I’ve contacted the developer that made the change that broke me, but I haven’t heard back. Hopefully he’ll be able to point me in the right direction.

I can’t stress this enough. PLEASE test on Aurora and Beta if you have the bandwidth to do so. These Firefox 14 issuse should not have been found after Firefox 14 was released. And yes, I’ll admit that I’ve been failing in my testing as well, but to be blunt, I’m not paid for any of the time I spend on enterprise, so it’s not one of my top priorities.

Please note: I reserve the right to delete comments that are offensive or off-topic.

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15 thoughts on “MAJOR Change Setting Default Preferences for Firefox 14

    • CCK is the Client Customization Kit which is an add-on I created to help with enterprise deployments.

      GRE stands for Gecko Runtime Environment. It’s the parts of Firefox that can be shared among other apps like Thunderbird.


    I’ve spent the last 2 hours trying to figure out why my stupid prefs.js wasn’t being loaded and all the documentation I found pointed to defaults/prefs.


  2. Hi Mike,

    I’m trying to find the setting to get the bookmarks toolbar to show by default. I tried searching the about:config for bookmarks and bookmark – do you know the setting by chance?


  3. Thanks for the update on “prefs” vs “preferences” and the “browser.startup.homepage” clarification. Saved me a lot of work.

    I do notice that some of the configuration values wont’ set, regardless of what you set them to, or where they reside. I.e. on a test XP VM (running 15.0.1) “app.update.enabled” seems to be ignored completely.

    Thanks again.

  4. Things are getting more and more interesting. At least as of Firefox 23.0.1 using ‘defaults/preferences/’ directory doesn’t work at all. Now ‘browser/defaults/preferences/’ should be used.

    Using ‘defaults/pref/’ is still OK, but values set here won’t override values stored in omni.ja. That’s the case with ‘extensions.autoDisableScopes’ – it could be overridden only from ‘browser/defaults/preferences/’.

    • To be more accurate values in ‘defaults/pref/’ directory override values in /omni.ja, but not in browser/omni.ja. It seems that files are processed in following order:

      As usual values in latter files override previous ones.