Sohail Mirza, standing in for Peter.

Helpful Hints – Running multiple instances of Firefox

Ever wanted to run more than one instance of Firefox? At the same time? It’s quite simple, really!

The advantages of doing this are apparent to those who might be in a multi-user environment using only one account on the PC. Also for web developers who may have a separate Firefox profile for development, and another one for regular browsing, this is a useful ability.

The way to do it is to set up a Firefox shortcut with the link target being:
"C:\Program Files\Mozilla Firefox\firefox.exe" -p -no-remote
You would, of course, want to modify the path to the Firefox executable depending on where you’ve installed it.

In Ubuntu, your application launcher should reference the following:

/usr/bin/firefox -p -no-remote

The keen observer will note that we’re actually providing two different command-line switches to Firefox. The “-no-remote” tells Firefox to launch in a new process, and the “-p” switch tells Firefox to bring up the Profile Manager. Without the profile manager switch, Firefox will simply try to load your default or last used profile, provided you haven’t setup Firefox to bring up the Profile Manager every time you start it.

Written by Sohail Mirza

June 11, 2007 at 10:28 am

Posted in Firefox, Helpful Hints

7 Responses

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  1. It was very helpful, that’s what I’ve been missing. Thanks a lot 🙂


    December 31, 2008 at 6:01 pm

  2. […] Created a default shortcut to launch multiple instances of Firefox. […]

  3. Cool! I’ve been looking into multi-browser compatibility for my websites.

    This, the old Firefox version page on and My DebugBar IETester should go a long way towards helping…

    Now I’ve just got to look into tackling Safari and Opera…


    March 19, 2009 at 6:00 am

  4. Be careful with the papa option (ProfileManager abbrev.). Per the link below it needs to be “-P” (uppercase) on Linux systems.

    Ted K.

    April 3, 2010 at 1:11 pm

  5. I want to load extensions automatically without restarting firefox when ever i do a modification.
    Is that possible. Now when i change a js file for an extension i need to close and reopen firefox for the modification to take effect. instead is that any method to reload the modified js file without restarting firefox?

    Jayapal Chandran

    May 18, 2011 at 4:03 am

    • Jayapal, Firefox 4.x introduces restartless addons (also called Bootstrapped extensions). These are addons that do not require a browser restart. You can read about them on the Mozilla developer wiki.

      Sohail Mirza

      May 18, 2011 at 9:11 am

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