You can modify prefs.js to set default preferences for a user.

The file has a somewhat unique format, but it’s pretty straightforward to change. You can modify bookmarks.html to add or remove bookmarks. The other thing you can do is modify the existing files. I’ve seen cases where someone started Firefox, added the certificates and certificates authorities they needed and then copied the various *.db profiles from their profile and put them in the default profile so all their users would get them. This is most commonly used if you want to have default certificate databases. If you add additional files into this directory, those files are copied into the default profile along with the rest of the files.

You have a two choices when it comes to modifying the default profile – changing the existing files or adding your own. When a new profile is created, these files (and any other files that are also in the directory) are copied over. You’ll see the following files in the browser/defaults/profile directory:Ĭopy the files you want to modify into the directory browser/defaults/profile underneath where the Firefox executable is located (you’ll have to create this directory). Make sure you unzip it into a temporary directory.

To retrieve the files you want to modify, unzip the file omni.ja(r) which is located in the Firefox directory. The contents of the browser/defaults/profile directory are copied over after the files in omni.ja(r). When you create a new profile in Firefox, the profile is prepopulated from the directory browser/defaults/profile in the file omni.ja(r) as well as the contents of the browser/defaults/profile directory where Firefox is installed. We’ll also take this opportunity to talk about userContent.css and userChrome.css which we mentioned earlier. It involves changing the files that Firefox uses when creating a new profile. This next method of customization is not as widely used, but it is still worth mentioning. I was not aware that Firefox copied the contents of the defaults/profile directory on the file system after using the files on omni.ja(r). Update: I have made major modifications to this post. I believe I’ve updated them all, but if you have problems, see this post. Update: The locations of the files in this post have changed. Update: This method no longer works in Firefox 46.

Reinstall firefox profile os x