Firefox allows to use multiple profiles independent of each other on the same pc,yet most people are not aware of this.
Let’s delve into this!
A Firefox profile stores the various extensions,settings,history,bookmarks and so on.
As it happens with all powerful programs built modularly,it can happen that may be become slow,and this happens with Firefox too.I’ve become aware of this possibility to switch between profiles while searching how to restore Firefox whilst keeping the files above.
By installing this ProfileSwitcher extension you will be able to open a new,separated instance of Firefox either from the file menu or the addon bar.
Of course to use it properly you need to have at least two profiles or all this would be pointless,in my case I’ve created two profiles named Base and WebDevelop.
Inside Base I’ve installed all the extensions that I routinely use,such as Scriptish (GreaseMonkey’s fork) Youtube2Mp3 and others.
Inside WebDevelop I’ve installed Firebug, HtmlValidator and other comparable extensions.Adblock Plus is installed in both profiles.
How to create a profile
Once you’ve installed the extension,restarted the browser and opened the menu,click on the profile manager,then create a new profile.
Start this profile and install the extensions you need,your favoured theme and so on.
Then do the same for the second profile.
Backing up a profile
There are two option here,one is using Sync (read below),the other is the manual way.The latter is more comprehensive because it allows you to save also passwords and other data.
I will refer you to the Firefox wiki which has a detailed explanation of the files in the profile and their content.
Of course in order to avoid overwriting some files,you’ll have to transfer files while Firefox is not running.
This feature is very simple to use and I advise you to read the official guide for Firefox sync.
Set the same profile on both the new and the old in the need to create new starting so take your bookmarks, history, depending on what you set that you will do the backup.
These two extensions create their own folders inside the profile folder,storing the actual scripts and their settings database.
For greasemonkey you’ll have to copy and paste the gm_scripts folder,whilst for scriptish the folder is named
In case you’re wishing to have some predefined,inalterable Firefox settings without having to deal with about:config, you’ll have to add an user.js file inside the profile folder, of which I’m providing an example here based on my own file with some optimizations:
//support for ed2k link
//fix for middle button on Unix
Osmesalib is needed by Firefox to use Mesa for WebGL rendering, so you’ll have to adjust the path for your own pc.
Removing the old profile
You can eventually remove the default profile from the profile manager window.
What may be the advantages of doing this?
You can have several Firefox instances customized according to different needs in order to have a better web experience and also increase Firefox’s speed.
An year ago the Mozilla Foundation designed a page in which were displayed the extensions most likely to cause slowdowns, with Firebug being the number one.
By having separate instances you can group the web developer kind of extensions in a dedicated profile, therefore avoiding to slow down your regular web browsing experience.
Lifehacker’s bloggers do take advantage of this feature, as you can read here.
You can also grab the chance to do some cleanup,because if you are anything like me in trying many extensions,you have no idea of what a mess will become the prefs.js file and the profile folder… lots of rubbish in there!
Thanks to Geko for the english translation!