Running several Firefox versions simultaneously

21 Oct

Ever been in the need of running more than one instance of Mozilla Firefox? Well, I have. Multiple times.

I use Firefox for my browsing and development. Combining both in the same profile has been a pain many times especially when ones development is intensive leading to high memory and CPU consumption unfortunately ending with a browser crash.

Some time ago I starting using Firefox Beta since it included the Sync feature built-in. At some point I wanted to revert back to the release version again as the add-ons needed to be ready for Beta as well and it could take the add-on authors some time to update leaving them disabled till then.

The easiest thing is to run two or more versions simultaneously of Firefox which provides you with increased flexibility, especially if you do web development of any type.

To proceed simply download another version of Firefox and install selecting the custom choice. Make sure you install it in a different path than your current Firefox installation.

The key to get more than one instance of Firefox running is to use multiple profiles. To create an additional profile for your next version open the command prompt (if on Windows) and type the following:

"C:\Program Files\Mozilla Firefox" -profilemanager -no-remote

Obviously change the path to match your own system if needed.



Now the profile manager should be open and you can simply create a new profile and call it something else like e.g. “BETA”. Then click “Exit” afterwards to quit the profile manager.



Next you need to edit the launcher of your newest installation of Firefox, by right-clicking its icon in the Start menu and selecting Properties. At the first text box add the following to the path:

-P yournewprofilename -no-remote

So it looks something like this:

"C:\Program Files\Mozilla Firefox Beta\firefox.exe" -P BETA -no-remote


Save and launch your second instance of Firefox by clicking on the same icon. You should now see two different “Firefox.exe” processes in your task manager.



In that same screen you were before you can also change the title and icon itself so that it is easier to distinguish which version is which.


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