Run Multiple Instances of Firefox Portable and Firefox 3.5 together

Firefox is one of the best browsers and most of us are using it as a default browser. One of the best features of Firefox is that it supports add-ons. But if there are many add-ons, loading time taken by Firefox will be more.

I found a solution to this problem. At first downloaded a Portable Version of Firefox and installed all the required add-ons in the Portable version.

Removed all the unnecessary add-ons from official version of Firefox 3.5. This made Firefox 3.5 to load faster and used it for browsing.

But, when I tried run both portable and official version of Firefox together, it gave a message saying “Another instance of Firefox is already running“.

How to run both Portable and Official Firefox together?

Download Firefox portable edition and Install it in a separate folder in C drive.

Then copy the FirefoxPortable.ini file from Source folder, which will be located in C drive > Program Files > Firefox Portable > FirefoxPortable > Other > Source.

Paste FirefoxPortable.ini file in the folder where Firefox portable.exe file is located.

Edit the FirefoxPortable.ini file. Open it with notepad, there is an option “AllowMultipleInstances=false“, change it to true and save.

Close all Firefox sessions.

Now open both Portable Firefox and Firefox 3.5 together, both will work without any error. Feel free to run two instances of Firefox.