I wanted to check out the latest nightly build of Mozilla’s Firefox browser (currently version 3 alpha), but I didn’t want to uninstall my current version or overwrite, or screw up my profile and all those extensions I have installed. So how do you run two builds of Firefox at once? Pretty easily actually (while the following instructions are for Windows, similar actions can be used with Linux or Mac)!

First create a new profile

This is actually really simple, you just need to do one of two things:

Select Case

Case 1

From a command prompt or Start menu > Run type:

“[path_to_firefox]\firefox.exe” -CreateProfile [profile_name]

For most of us running Windows this will look like:

“C:\Program Files\Mozilla Firefox\firefox.exe” -CreateProfile test

(“test” would be the profile name in this case)

Case 2

You can create a copy your Mozilla Firefox shortcut on your desktop, right click and select properties, then add the -CreateProfile [profile_name] in the “Target” field on the “Shortcut” tab of the properties dialog. Then click OK and double click the shortcut.

End Select

In either case, Firefox will create the new profile and not open any windows.

Now that you have a new profile you need to be able to open your new browser with the new profile (I’m assuming that you’ve downloaded a new browser and have extracted or installed it to your liking).

Create a new shortcut to you’re new browser

You can either copy your shortcut (if you’ve installed it) or create a new shortcut to the new version of firefox.exe, then (just like in Case 2 above) right click on the shortcut and in the “Target” text box, add -P test (or whatever you’ve used as your new profile’s name) to the end of the quoted firefox.exe path. The click OK.

Now, if you simply double click this icon you’ll open a new instance of your new browser build and you can start to play.

Just in case you want to use both your old browser and your new browser side-by-side

So, you say you’re curious if that website looks the same in your old browser as it does in your new browser, and you need them both open to tell? Well that’s no problem either. Open up the shortcut properties to your new browser just like you did above and after the “-P test” add in “-no-remote”. Now you can open multiple profiles, which should allow you to open your old browser and new browser side-by-side.

Have fun!

Reference Links from mozillaZine knowledge base:
Profile Manager
Command line arguments

This entry was posted on Monday, June 25th, 2007 at 11:23 am and is filed under Firefox, Linux, Tip, Windows. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.