Firefox global extensions, again

Previously, I have written on deploying Firefox extensions globally, and using the Firefox Client Customization Kit (CCK) to customize Firefox for your organization.

Using the CCK involves creating a Firefox extension, and most likely, you’ll want to deploy it globally. A few commenters on the CCK post were confused about the details around that, so this post is an attempt to clear all that up.

Firefox extensions are distributed in the form of an .xpi file, which is really an archive of a bunch or files and directories. When you double-click an .xpi file (or otherwise tell Firefox to use it), Firefox unarchives the contents and copies them into the current user’s profile directory.

Before unarchiving the xpi and installing it in the user’s profile, Firefox prompts the user to make sure it’s OK to do this. This is not a good fit for extensions you want to seamlessly deploy to all your users.

So instead, you must install the unarchived extension in the global extension location, which for Firefox on OS X is:

/Library/Application Support/Mozilla/Extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}

You cannot just copy the .xpi file there. If you do, users will still be prompted to install it because it’s still in its archive. Instead, you must unarchive the extension, then copy it there. I find the easiest way to do this is just double-click it and let it install in your local user profile, then copy the unarchived extension from your user profile to the global extension location — something like:


cd /Users/gneagle/Library/Application\ Support/Firefox/Profiles/cuak0rwz.default/extensions
cp -R myorg-cck@extensions.myorg.com /Library/Application\ Support/Mozilla/Extensions/\{ec8030f7-c20a-464f-9b0e-13a3a9e97384\}/


After you verify it works as you’d expect you can then use your favorite packaging and/or distribution tool to install the unarchived extension on all your managed machines.