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I am trying to run Firefox 8 and Firefox 5 versions at the same time on my Windows 7 machine.

Firefox 8 is my default browser and I installed Firefox 5 using custom options in a separate folder. I created a new profile for Firefox 5.

I am able to load both versions individually using

"C:\...\Mozilla Firefox 8\firefox.exe" -p default


"C:\...\Mozilla Firefox 5\firefox.exe" -p "Firefox 5"


However, I am not able to load them simultaneously. I even tried the -no-remote option. When I use the -no-remote option, it is trying to load the no-remote website.

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Something is screaming out from my head, "Why the **** would you want to do that?" :) – Mehrdad Nov 13 '11 at 6:08
What do you mean by "trying to load the no-remote website"? – netvope Nov 13 '11 at 6:10
@Mehrdad: New versions can bring new bugs. – Ignacio Vazquez-Abrams Nov 13 '11 at 6:18
@IgnacioVazquez-Abrams: Ah, I see. Although, to be honest, I have seen little difference from version 4 to version 5, and observed no difference from then up to version 10. I have no idea what the heck they're doing... is there any difference between versions 5 and 10, to make me want to use both? – Mehrdad Nov 13 '11 at 6:25
up vote 2 down vote accepted

These steps are for the FF2 and FF3 so I think they will work with the FF8 and FF5 as well. For more information you can go on the Source link I've provide bottom of the answer.

First, you should create a new profile just for testing Firefox 3. You should do this to keep your precious Firefox profile safe from any problems in Firefox 3. Otherwise, Firefox 3 will use your current Firefox 2 profile by default. You can create a new profile easily with the Profile Manager, which you can access by running:

/path/to/firefox -profilemanager -no-remote

If you get confused, the official Firefox website has more detailed instructions on how to create a new profile You can start up Firefox 2 normally (just so you can see Firefox 2 and 3 running side by side).

We’re gonna run Firefox 3 using our newly created profile.

/path/to/firefox3 -P minefield -no-remote &

Firefox 3 should start up with your new clean profile!


share|improve this answer
Firefox 8 with no parameters, and Firefox 5 with '-P "Firefox 5" -no-remote' did the trick for me. – Ctroy Nov 13 '11 at 11:46
Really happy that its worth for you. – avirk Nov 13 '11 at 13:05

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