Installing and running multiple versions of Firefox.

Discussion about official Mozilla Firefox builds

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Post Posted July 10th, 2011, 2:30 am

Installing multiple different versions of Firefox.

A. The easiest way is to use the Mozilla Firefox, Portable Edition from Portable Apps for your 2nd and subsequent different versions of Firefox.
Older versions are here - ... ble%20Ed./
The Portable versions can be installed to your hard drive and they won't interact with your "official" Firefox installation or with each other. The downside is that Portable Apps doesn't usually offer pre-release versions until late in the Beta stage, and with Mozilla's new fast release schedule in 2011 there may not be that many pre-release versions offered by Portable Apps.
For launching Firefox Portable as multiple simultaneous instances, you would need to edit the FirefoxPortable.ini file and change the AllowMultipleInstances=false preference to true.

B. When installing multiple official versions of Firefox, the main thing to keep in mind is that each different version needs to be installed in it's own unique program files folder (use the Custom Installation option on the Setup Type page of the installation routine) and each version should have its' own Profile; you also need to make sure that you always launch each version with the appropriate Profile.If you don't use the Custom option, Firefox will overwrite the prevoius installation in Program Files. If you are installing multiple versions, do not launch Firefox at the end of the installation procedure, see the section below about dealing with running multiple Profiles.

Also, when you are installing multiple versions of Firefox you need to be aware of is that the last installer version of Firefox / Aurora / Beta / Nightly that you install will become the "default" in the Windows Registry, if you happen to use Firefox as your default browser that can cause problems for you. Because of that, you are better off using the Zip-archive builds of the Aurora, Beta, and Nightly versions, the Zip-builds don't write to the Windows Registry.
Aurora -
Nightly Trunk -

Note: You can create your own "Zip-build" of Firefox 4+ versions by opening the Firefox Setup #.0.exe package with 7-Zip and extracting the contents \code\ folder into a new program files that you created ahead of time. Versions prior to 4.0 aren't that easy to "extract".

Dealing with running multiple Profiles.
This is basically the same whether you are using different versions of Firefox, or you want to run multiple Profiles for the same version of Firefox, or a combination of both. There are a few ways of running multiple Profiles, (see the hyperlinks to my older threads about this topic at the end of this posting) but IMO the easiest way of doing it for newer users is with the new Profile Manager XUL Runner application, that reached the 1.0 stage on May 17,2011. Written for and images for Mac OSX. I will cover Windows below.

Create a Program Files files folder - like Profile Manager XUL Runner - and extract the contents of the Zip file into that new folder.
Right-click the profilemanager.exe file and use Send To > Desktop (Create Shortcut)
Double-click that shortcut to launche the Profile Manager Application.

General info if you're not using the Profile Manager XUL Runner application:
For running multiple versions of Firefox at the same time (simultaneously) you basically need two things; the first is a separate Profile for each version, and the second is the -no-remote switch in the target line.

As in - "C:\Program Files\Mozilla\Firefox 16.0\firefox.exe" -no-remote -p "Profile-name"

If you are using a Profile in a non-default location, you may need to use -Profile instead of using -p.
As in - "C:\Program Files\Mozilla\Firefox 16.0\firefox.exe" -no-remote -Profile "Profile-name"

I have written three similar threads here in the MozillaZine Builds forum about multiple Firefox version installations and running multiple simultaneous Profiles over the years, with valuable input from other MozillaZine forum members.

Last edited by the-edmeister on November 16th, 2012, 3:27 am, edited 4 times in total.
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Post Posted July 10th, 2011, 2:41 am

If anyone finds an error or this needs correcting, please PM "the-edmeister" or a moderator & it will be rectified.
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Post Posted April 18th, 2014, 9:16 am

This guide has been replaced by a new guide here: viewtopic.php?f=23&t=2821799
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