Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

How to copy an new user.js over an existing one in the profile

  • 6 cavab
  • 1 has this problem
  • 1 view
  • Last reply by Slade0764

more options

Hello, i am silent deploying Firefox on many Pcs at a time. The Computers now have Firefox 14 on it and the people work with it well. I ve deployed it with setting changes in the user.js. Now i must deinstall the Firefox 14 and install Firefox 16 ... the firefox profile is still in the userprofile. Now i want to change silent one line in the user.js in my userprofile.... i do the new user.js in the <Programfiles/Firefox/defaults/profile> folder... but the new user.js do not copy in my userprofile and overwrite the old one... I am searching for an solution to add one setting in my user.js or pref.js in my old profile... Greeting Joe

Hello, i am silent deploying Firefox on many Pcs at a time. The Computers now have Firefox 14 on it and the people work with it well. I ve deployed it with setting changes in the user.js. Now i must deinstall the Firefox 14 and install Firefox 16 ... the firefox profile is still in the userprofile. Now i want to change silent one line in the user.js in my userprofile.... i do the new user.js in the <Programfiles/Firefox/defaults/profile> folder... but the new user.js do not copy in my userprofile and overwrite the old one... I am searching for an solution to add one setting in my user.js or pref.js in my old profile... Greeting Joe

Chosen solution

hello manowar30, i think you can better achieve this by using the mozilla.cfg file in the programs folder. for reference refer to http://kb.mozillazine.org/Locking_preferences

Read this answer in context 👍 2

All Replies (6)

more options

Seçilmiş Həll

hello manowar30, i think you can better achieve this by using the mozilla.cfg file in the programs folder. for reference refer to http://kb.mozillazine.org/Locking_preferences

more options

hi manowar30, you mean that the editing user.js file does not saved in the profile folder?

Editing user.js entries


thank you

more options

No, i already have an user.js in my profile. now i install the new version of firefox but the new user.js do not overwirte the old one in the profile...

i ve copied it to ../firefox/defaults/profile

from there it should be copied in the profile but it do not overwrite the old one in the profile...

more options

I thing you must try madperson's reply (the locking preferences)

thanks again

more options

You can use these functions in mozilla.cfg:

defaultPref();  // set new default value
pref();         // set pref, but allow changes in current session (prevails user.js)
lockPref();     // lock pref, disallow any changes
more options

You need to create a batch file.. to copy the user.js file into the profile directory. The problem is... 1st The directory generates a random name when installed. 2nd it places a . in the directory name it creates. copy will not work.

To get around this .. there is a simple "for" command you can place in a batch file and will do the trick. example shown below.


set folder=%APPDATA%\mozilla\Firefox\Profiles

for /f %%i in ( ' dir /a:d/b "%folder%" ' ) do if exist "%folder%\%%i\." copy /y "C:\pathtofile\user.js" "%folder%\%%i\">nul

Modified by Slade0764