The magazine of the Melbourne PC User Group Running two or more versions of Firefox concurrently Barry Andrews |
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This applies to Windows XP but can be adapted to other versions of Windows as
well as Mac and Linux OS. |
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Now that Firefox 3.5 is here, I thought I'd upgrade to it as it is faster and
more secure than its predecessor, version 3.0. But no sooner did I upgrade than
I discovered some of my favourite plugins no longer worked, as their
developers had not yet updated their code! If this happens to you, here is how
to have your cake and eat it. When you install Firefox in Windows, the default directory for initial installation and upgrades of the program's working files (firefox.exe, etc.) is C:\Program Files\Mozilla Firefox. However, Firefox's *settings* such as bookmarks and plugins are located in its Profiles directory, C:\Documents and Settings\[username]\Application Data\Mozilla\Firefox\Profiles. I have found it handy to create shortcuts to both folders (or maybe just the "Program Files" and the "Application Data" folders) in Explorer Favorites, for easy access. In the Profiles folder is a subfolder named xxxxxxxx.default (where xxxxxxxx is a unique 8-character ID) containing your bookmarks, plugins and settings. So how can we install a different version of Firefox without overwriting our existing one? For this we need its Profile Manager.
Firefox's Profile Manager |
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In my case I had already installed Firefox 3.5 but I wanted to be able to run
Firefox 3.0 to get the plugins
working again, and kept the Setup programs for each version on my hard drive. At
this point we must decide whether to leave the default profile (v3.5) as it is
and create an additional profile for v3.0, whether to rename the default to
"Firefox 3.5" and create a new one named "Firefox 3.0", or whether to save the
contents of the default, delete it and start afresh, creating a profile for 3.5
and another for 3.0? The first choice is the correct one, as you will see.
Before we get underway, try this simple test. Assuming Firefox is set as your
default browser, open it and also a *non-browser* application (such as a Word
document) containing web links. Click a couple of links and make sure each one
opens in a Firefox tab or window, depending on the option you chose. If the
famous "Firefox is already
running" message (below) did *not* appear, you are safe to proceed, otherwise
see the Troubleshooting section at the end of this article.
Taking the moz* off MOZ_NO_REMOTE
If you research the Profile Manager you may read about a Windows environmental
variable named MOZ_NO_REMOTE, set to 0 (off) or 1 (on). Think of it as just a
big switch that makes Firefox indifferent to the existence of another
instance of itself, to which it would otherwise object! MOZ_NO_REMOTE was used
with Firefox 1.5.0, but Firefox 2 replaced it with the -no-remote parameter,
which does virtually the same but can be fitted neatly into Firefox's
command line in a similar way to -ProfileManager.
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Let's begin by creating a nice little shortcut icon to invoke the Profile
Manager; you will use this technique
later to create a startup icon for v3.0. Make a copy of the standard Firefox
shortcut icon that's probably on your desktop or Windows taskbar, and rename it
Profile Manager. Open its Properties and its Target should be "C:\Program Files\Mozilla
Firefox\firefox.exe". Fine. (not forgetting the initial hyphen) so that it's
exactly the same as the command used by Run, above. Make sure Firefox is closed before running the shortcut, and the Profile Manager should open. This shows that the Profile Manager is really a little program hidden inside Firefox. (The extension -ProfileManager is called a parameter, a.k.a switch.) Finish by changing its icon to something more appropriate (hint: look in C:\WINDOWS\system32\shell32.dll). Next, install Firefox 3.0 not in the default directory, but elsewhere; when you reach Setup Type, choose Custom and change the Destination Folder to C:\Program Files\Mozilla Firefox 3.0, also changing its Start Menu Folder to Mozilla Firefox 3.0 to avoid overwriting the default. Don't run it after installation. Now we will create a profile for it. You might ask, how can we make sure the new profile opens FF 3.0 and not 3.5? The answer is that the profile is independent of the actual version used. Let's see how it works. Run Profile Manager and create a new profile named firefox30 (case is unimportant here, but avoid spaces in the name or you will have to enclose it in double quotes). When finished, the Profile Manager window should look like this (at right): |
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while your Profiles Folder should now contain a new folder named
xxxxxxxx.firefox30.
Now, make another copy of your Firefox shortcut, this time appending -no-remote
-P firefox30 to the Target so that it reads:
"C:\Program Files\Mozilla Firefox 3.0\firefox.exe" -no-remote -P firefox30.
You can work out that this shortcut will open FF 3.0 while the -P (Profile)
parameter directs it to use firefox30. We could have left it at that and enjoyed
being able to alternate between different FF versions, but with the -no-remote
parameter we can run them concurrently!
There's one catch to this arrangement, though. As the Mozilla KnowledgeBase
states(http://kb.mozillazine.org/
Opening_a_new_instance_of_Firefox_with_another_profile), "Be aware that you
can't send links from an external program to a Firefox instance that is started
with the -no-remote switch, or if the environment variable MOZ_NO_REMOTE is
set." That's why we test activated an external link first. This limitation
simply means that you
have to *copy and paste* such links into concurrent instances of Firefox instead
of activating them directly.
For this reason I advised you not to alter the default installation as this is
where you will need this ability
most. If you decide you need remote link activation in v3.0, you could create
two shortcuts, each using 3.0 and the firefox30 profile, but only one including
the -no-remote parameter.
Finish by renaming this shortcut "Firefox 3.0" and assigning it a distinctive
icon, if you wish.
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The big moment arrives Now it's time to test your work. Clicking the default "Mozilla Firefox" icon should bring up 3.5 with your bookmarks and other tweaks. Without closing it, clicking the "Firefox 3.0" icon should bring up 3.0 as a brand new installation in a new window, minus bookmarks and plugins, of course. Now you can add that favourite plugin, a copy of your bookmarks (use Organize Bookmarks -> Restore from your Default profile), set the home page, and you're ready to go! Buoyed with this success, I went on to create a third profile named webdesign, for my SIG group, using v3.5 to run it. This offers the benefit of having customized bookmarks, fonts, etc., entirely separate from my own personal profile. I could of course have opted for a Windows User named Webdesign, but this wasn't necessary. Troubleshooting If the dreaded "Firefox is already running" message locks you out despite your best efforts, there are several steps you can take to clear it. First, try simple rebooting. Firefox normally creates a zero byte file named parent.lock (in Windows, different names in other OS) which prevents you from opening a second instance of it (not a second window). If Firefox crashes, this file may not be removed; you may have to delete it from your profile folder, or kill the Firefox process if it is running and start again. On one occasion, nothing worked until I installed 3.0 over 3.5, which fixed it. I then reinstalled 3.5 and continued normally, re-testing links as I progressed. This may work for you. There is plenty on the Web about this - Google found it mentioned in over 34,000 web pages! |
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*"To put the moz on": To put an evil influence on a person; to jinx. Moz is an
abbreviated form of mozzle, a borrowing from Hebrew mazzal meaning ëstar or
luckí. It probably came into Australian English via German Yiddish speakers.
First recorded 1924.
http://www.anu.edu.au/ANDC/res/aus_words/aewords/index.php
About the author:
Barry Andrews is the convener of the Web Site Design SIG which meets on the 4th
Tuesday of every month.
