Max, you may need to use the locked profile preference:

Step:1) Created a file name like "local-settings.js" in -- /usr/lib/firefox/defaults/pref --- Pasted this line -- pref("general.config.filename", "mozilla.cfg"); --- in "local-settings.js" Step :2) Created a file name like "mozilla.cfg" in -- /usr/lib/firefox --- And copy and paste the below line in this "mozilla.cfg" file.

defaultPref(); // set new default value pref(); // set pref, but allow changes in current session lockPref(); // lock pref, disallow changes

More info: Mozillazine:Locking Preferences

hi, thanks for your time. just a couple of questions. i am working on a windows server and those directories do not exist. i have c:\usr and c:\usr\snmp only. how do i create the js and cfg files? do i need a special program? regards, max

The js and cfg files are plain text files. On Windows, the lock files are stored in the program folder ("installation directory"). If you didn't already, check out the Mozillazine link for more information.

The file path that Rachel posted are for Linux. On Windows this is usually one of these locations:

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• http://kb.mozillazine.org/Installation_directory

Place a local-settings.js file in the defaults\pref folder where also the channel-prefs.js file is located to specify using mozilla.cfg.

pref("general.config.filename", "mozilla.cfg");
pref("general.config.obscure_value", 0);

These functions can be used in the mozilla.cfg file:

defaultPref();	// set new default value
pref();		// set pref, allow changes in current session
lockPref();	// lock pref, disallow changes

See also:

• http://mike.kaply.com/2012/03/16/customizing-firefox-autoconfig-files/

hi cor-el i placed those 2 files in the c:\program files (x86)\mozilla firefox is that it? how do i know if it worked? regards, max

i am a little bit confused. i placed the local-settings.js in C:\Program Files (x86)\Mozilla Firefox\defaults\pref

and place a txt file called mozill.cfg in C:\Program Files (x86)\Mozilla Firefox

is this correct? how can i know if this worked?

regards, max

Hi max, if the files are working, the preference(s) you set in the .cfg file are locked against changes inside Firefox.

To check:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste mix and pause while the list is filtered (assuming the relevant preference(s) have mix in the name)

The preference(s) you locked should have a special status (i.e., not default and not user set) and if you try to edit them, Firefox should not save the change.

Does that check out?

Locked prefs should appear in italic and have a status locked. You can click status header to sort by this header and locked prefs should appear at the top (you may need to click twice to reverse the order).

to all of you, thank you very much for your time and help. Just need some URGENT help here. I applied the suggested solution and now my gpo to launch firefox with a specific homepage stopped working. how do i uninstall your suggestions? i searched for the mozilla.cfg file and it looks very different to what i did and the JS file is not there anymore.

any clue? regards, max

How were you setting the home page? Since there can only be one of these configuration lock files, make sure all the preferences you want to set get in there together.