Today a scenario came up where I needed to run an older version of Firefox to make sure that there was full support for an applications web interface that I was using. There is not standard way to do this though following the steps below will allow you to install and run multiple Firefox versions without much hassle.
Install Multiple Firefox Versions On Mac OSX:
- Download Older Firefox Version: Click here to download Firefox 3.6.28.
- Begin Firefox 3.6.28 Installation: Double click the file you just downloaded which will be something like “Firefox 3.6.28.dmg” and will display a window similar to the below. Instead of dragging the Firefox icon to the applications folder as displayed in the below window drag it to the desktop so we can modify it.
- Modify Firefox.app Folder Name & Install: Now delayed double click the Firefox.app on your desktop so you can rename it to something like Firefox3628.app as shown in the below example.
Once the application folder is renamed you can now move it into the Application folder but be careful not to launch it yet.
- Create Firefox Profile On OSX: Open a Terminal window and type the below two commands to launch the Firefox Profile Manager shown in the below example image. Make sure to modify the folder after /Applications/ to whatever you named in step 3.
Click the Create Profile button to begin the Firefox profile creation process. The first window will display an Introduction to the Profile Manager so click Continue to move to the next screen. Modify the name to something like Firefox3628 an click the Done button to generate the profile. Now back at the Firefox Profile management window you will display two profiles as shown in the below example. Before you exit the Profile manager I suggest removing the check from the “Don’t ask at startup” also shown in the below example image.
Having two profiles will allow you to run both versions of Firefox at the same time without issue.
Now when you launch either version of Firefox the Profile Manager window will display. For the latest and greatest Firefox version which is currently Firefox 11 highlight the default profile and click the Start Firefox button and for the older version of Firefox which in this case is Firefox 3.6.28 highlight the Firefox3628 profile and click the Start Firefox button. You now are able to successfully run multiple versions of Firefox without issue. You could also follow the same directions and install as many version of Firefox as you like for testing or whatever the reason may be.
Application Icon Note: If you would like to modify the older Firefox versions icon so you can keep both Firefox versions in your dock without being confused on which one you are running follow the directions in this Question Defense article.