As a web developer, it is important to test against upcoming versions of popular browsers. With Firefox 3 sitting in our door step, you may find this little how-to useful : a quick ‘n easy way of running Firefox 2 alongside Firefox 3 beta 2 in Five steps: the principle is two have 2 user profiles, one for each Firefox version.

1./ Download and Install Firefox 3.

It will install itself in a different folder (Default in C:\Program Files\Mozilla Firefox 3 Beta 2).

2./ Go to your Firefox 2 Folder

(normally: C:\Program Files\Mozilla Firefox).

3./ Create a new profile

right-click on firefox.exe, choose “create shortcut”, rename the created shortcut as “Profile Manager” (wonder why Mozilla don’t provide it already), then right-click on the created shortcut, and in the first field “Target” (Cible in French): append this to the existing value (after the double quote):

-profilemanager -no-remote

So that it reads:

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

Now, double-click on it and choose “create new profile”, call it “FF3” (or anything you like, but make it simple).

4./ Got to your Firefox 2 folder:

Again, create a shortcut to the firefox.exe file sitting in this folder, right-click on the sortcut > properties. In the target field, add this to the current value:

-P FF3 -no-remote (replace FF3 with the name you put in step 3).

So that it reads:

"C:\Program Files\Mozilla Firefox 3 Beta 2\firefox.exe" -P FF3 -no-remote

(Mac / Unix users: add a “&” at the end:Â Â -P FF3 -no-remote & )

5./ Now copy that shortcut to FF3 wherever you want (desktop, menu bar…) And make sure you use it to launch Firefox 3!

Thanks codefront for the tip !