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As far as I know, mozilla firefox creates a directory in home folder/local settings in case of windows. So when I try to run firefox 4 rc and firefox 3.x only one is launched, is it possible to have these two run side bye side?

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migrated from Mar 23 '11 at 12:07

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There's no reason to be using Firefox 4 RC1 or RC2; RC2 was renamed to final yesterday. – Hello71 Mar 23 '11 at 22:02

In some cases you may need to pass -no-remote in order to inhibit Firefox from opening another window from the existing instance instead of starting a new instance.

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Yes, I do it. You can use the same profile (it will disable extensions, etc. if they're incompatible), or create multiple profiles. See this article and the wiki.

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well this doesn't work for me, I am on Debian and my FF installations are in /opt and I created totally separate profile in totally separate folders, didnt work, the life hacker link doesn't work either – Kumar Mar 23 '11 at 5:40
@Kumar, what doesn't work? Did you just try just running firefox -ProfileManager (or firefox-4.0, whatever the case may be) and choosing? If that works, you can then setup a shortcut. – Matthew Flaschen Mar 28 '11 at 19:14
For ff3.6 and ff4, I used firefox -ProfileManager, created profiles for both in totally separate folders, one by one, then launched FF4 & tried launching ff3, didnt work, note that in when I launched ff I used profile manager param, then I tried using -no-remote, didnt work either, now the issue is ff3.6 is set as my primary browser and I have tried all possible things to set chrome as my browser but it wont work either :( – Kumar Mar 29 '11 at 3:40
@Kumar, you may need both ProfileManager and -no-remote. Did you try them in combination? As far the default browser, try these instructions. – Matthew Flaschen Mar 29 '11 at 15:41

Yes; it requires two things though.

  1. Create a new profile like Matthew says
  2. Pass -no-remote to firefox OR set MOZ_NO_REMOTE=1 (deprecated)
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Have you tried it? I am on Debian and have tried it but it doesn't work, may be am missing something... – Kumar Mar 24 '11 at 3:33

In answer to your question, Yes. Even if Firefox will only let you run one instance at a time, irrespective of the version number, then you can still get around it with third-party software which allows you to run more than one instance.

Try Sandboxie.

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sandboxie is for windoze, I cant even spell windoze correctly :P, but thanks, it will help others :) – Kumar Mar 23 '11 at 4:48

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