Running different versions of Firefox at the same time

Actions
Show content customized for:

Some advanced users like to be able to run two or more different versions of Firefox at the same time. To achieve this, the best approach is to have a different Firefox profile for each version of Firefox you want to run. (A profile stores all your important data, such as bookmarks, passwords, history, etc. For more information see Profiles.)

Using the same profile for different versions is not recommended as the unstable version of Firefox may corrupt your important data. Additionally, by using a different profile for each version of Firefox, you will be able to run all versions simultaneously rather than only one version at a time.

Table Of Contents

Back up your data

Before starting it is advisable to make a complete backup of your existing Firefox profile. For instructions, please see Backing up your information.

Setting up the other version of Firefox

Install the new version of Firefox that you wish to test in a different folder than that of your existing Firefox. Please note: You will have to install the additional version of Firefox outside your package manager.Please note: Do not choose to launch Firefox at the end of the installation.

Once you have the new version of Firefox installed you need to create a new profile for it to use. Please see the Managing profiles article on how to do this. Remember to invoke the profile manager using the new version of Firefox that you have just installed. Whilst you are in the Profile Manager, make a note of the names of the existing profile and of the new profile which you create.

Setting your default version of Firefox and your default profile

One of the versions of Firefox you have installed must be the system's default browser, and one of your profiles must the default profile that the default browser will use. This Firefox/profile combination will be the one used when you double-click on a locally stored .html file or click on a link in another program.

To set a version of Firefox as your default browser, please read the How to make Firefox the default browser article.

To set one of your profiles as the default profile the default version of firefox will use:

  1. From the menu at the top of the Firefox windowbar, select FileFirefox and then select the ExitQuit FirefoxQuit menu item.
  2. Invoke the Firefox profile manager with the version of Firefox you have made your default.
  3. Select the profile you wish to be your default.
  4. Click the Start Firefox button.

Starting the right version of Firefox with the right profile

You now have multiple versions of Firefox on your computer, along with a separate profile for each. You must now associate each version of Firefox with its corresponding profile.

Windows:
The first thing you must do is set up a shortcut which launches your default Firefox with your default profile.
  1. Make a shortcut to the firefox.exe file that you made your default browser.
  2. Right click on the shortcut icon and select Properties.
  3. In the Shortcut tab, find the Target text box. Ensure it contains something like:
    "C:\Path\To\Default Firefox\firefox.exe"

For the other versions of Firefox that you have installed:

  1. Make a shortcut to the firefox.exe file.
  2. Right click on the shortcut icon and select Properties.
  3. In the Shortcut tab, find the Target text box. It will contain something like:
    "C:\Path\To\Other Firefox\firefox.exe"
  4. At the end of the Target text add:
    -no-remote -p profilename
    Where profilename is the name of the profile associated with whatever version of Firefox you are currently editing. The Target text box will then read something like:
    "C:\Path\To\Other Firefox\firefox.exe" -no-remote -p profilename
Mac OS:
To start your default Firefox with your default profile:
  1. Open your Terminal.
  2. In the Terminal window, type:
    /Applications/Firefox.app/Contents/MacOS/firefox
    (Assuming Firefox.app is the version of Firefox you made your default)

To start a different version of Firefox using one of your other profiles:

  1. Open your Terminal.
  2. In the Terminal window, type:
    /Applications/Firefox_test.app/Contents/MacOS/firefox -no-remote -P profilename
    Where profilename is the name of the profile you wish to use, and Firefox_test.app is another installation of Firefox.
Linux:
To start your default Firefox with your default profile:
  1. Open your Terminal.
  2. In the Terminal window, type:
    /path/to/default/firefox/firefox

To start a different version of Firefox using one of your other profiles:

  1. Open your Terminal.
  2. In the Terminal window, type:
    /path/to/other/firefox/firefox -no-remote -P profilename
    Where profilename is the name of the profile you wish to use.

Copying data

After you have created your new profile, you may wish to copy over your important data from your old profile folder to your new one. Please read the Recovering important data from an old profile article for more information.

Troubleshooting

The wrong instance of Firefox opens

Double-clicking on a locally stored .html file, or clicking on a link in another program, etc, will always load in the version of Firefox that you made as your default, using the profile you made as your default. Instances of Firefox started with the -no-remote parameter ignore all links from such external sources.

When you try and view a locally stored .html file or you click on a link in another program, Firefox may give the error:

  • "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system."

This occurs when your default profile is already being used by an instance of Firefox that was started with the -no-remote parameter. To fix this you must:

  1. Set your default version of Firefox and your default profile (see above)
  2. Ensure that none of your instances of Firefox that get launched with the -no-remote parameter get launched using the name of your default profile.

Firefox appears to forget changes that are made

Your profiles are all independent of each other, so if you add a new bookmark in one version of Firefox then the other version will not have the same bookmark added. Therefore exercise caution when manipulating your important data within Firefox, and be aware that changes made to one version will not be replicated to other versions.


Did this article solve a problem you had with Firefox?

Was this article easy to understand?



Page last modified on Friday 30 of May, 2008 22:16:25 PST.
Contributors to this page: Chris_Ilias and stevee .
- This is a help article -

Search

User Tools

Tags in This Article