How can I run multiple versions of Portable Firefox in parallel?

Mango the Fruitarian August 26, 2010

I’m using portable Firefox version 3.5 and have downloaded a portable version of the upcoming Firefox 4. Is there anything I can tweak to let me run both versions side by side?

  1. Ross Willden
    September 3, 2010 at 12:31 am

    I use a sandboxing program (aptly named sandboxie) to do this. As long as you clear out the sand box at the end it will keep all your settings. You can even do this with different versions without them being portable.

  2. Mango Wodzak
    September 1, 2010 at 10:59 pm

    ok, josh, it looks like you were totally on the right track all along..

    just the .ini file i tweaked was not in the right directory.. i now have both versions running side by side, with the FirefoxPortable.ini in the main portable directory (not a sub directory) of both firefox versions, and with allowmultipleinstances set to read "true" in both, and both run in parallel .. thanks for your help!


    • FreeSoft4Down Inc.
      July 15, 2011 at 12:14 pm

      Thanks so much for your suggestion! I'd downloaded lastest portable version then spent whole day to let it run with current Firefox side by side. I've just found this post from google, lucky me!

      • Tina
        July 16, 2011 at 1:22 pm

        Thanks for your feedback.

  3. Mango Wodzak
    September 1, 2010 at 3:13 am

    any other ideas, as I'm quite sure this is doable, I just can't seem to make it work for me here.. i'm using windows 7.. ????????
    thanks, much appreciate all help..

    • Josh Fox
      September 1, 2010 at 8:47 am

      I was digging into it some more and it doesn't look like the profile manager was ever made portable. The problem comes in when multiple instances and versions of Firefox thinks it is trying to access the same profile, which is linked dynamically as Data/Profile/ in the BAT file that makes Firefox portable.

      I've tried a few things, but haven't been able to get anything to work the way you need. Even an extra portable app just for a second profile didn't work.

      • Mango Wodzak
        September 1, 2010 at 9:38 pm

        thanks josh, much appreciate the time you are putting in to this..
        actually, i am sure this is possible, as a german guy that runs a blog ( releases his own versions of portable firefox which are able to run in parallel.. so it can be done, i guess not as simply as i thought though..

        i just downloaded his latest version to see if this was still the case, and at this very second i have portable 3.6.8 (the english version from, and the german version from the mentioned blog, both running simultaneously..) so he's definitely pulling it off somehow.. any ideas how?

  4. Mango Wodzak
    August 29, 2010 at 9:05 pm

    hi josh,
    i wish i could report back to you that this worked, alas though, after changing the 2 firefoxportable.ini files to read allowmultipleinstances to be true, and then while having my default portable firefox 3.6.8 running, trying to start the portable firefox 4, all i get is a new instance of firefox 3.6.8 .. ie, this time i'm not getting the message saying another version of firefox is already active, but rather it just starts another session of the same running version. 3.6.8 ... any further ideas?

  5. Josh Fox
    August 29, 2010 at 4:13 pm

    Sorry about that, it's in the FirefoxPortable.ini file in the installation directory.

  6. Mango Wodzak
    August 29, 2010 at 5:37 am

    hmm.. thanks josh.. i think you are probably on to something there.. the only trouble is that when i do about:config, i can't see allowmultipleinstances in the list i'm given.. isn't there a file somewhere i should be editing and changing it to true?

  7. Mango Wodzak
    August 28, 2010 at 7:44 am

    hmm.. that doesn'r quite work.. it still tells me that another instance of firefox is already running..

    • Josh Fox
      August 28, 2010 at 10:02 pm

      Try opening about:config, search for "AllowMultipleInstances" and change it to true. This would have to be done in both versions to work. If there is a full installation on the computer too, you might want to change it there as well to keep it from happening in that case. This should make it work. Sorry about not mentioning this in my last response, I was think you meant just having both installed, not running at the same time.

  8. Josh Fox
    August 27, 2010 at 6:14 pm

    You should be able to rename the directories to include the version numbers so the PortableApps menu will treat them as separate applications.

    Since the apps are completely portable, all of the settings and data are stored in the install folder, so once they are renamed, they shouldn't interfere with the other.

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