A profile in Firefox is the collection of settings, customizations, add-ons, and other personalizations that a user has made or installed into their copy of Firefox. You can find details about profiles on Mozilla's end-user support site.

Reasons to have multiple profiles

The casual user may want to have different profiles for work and personal use, or different family members. Having different profiles would help separate work and personal life, or allow each family member to have his or her own set of bookmarks, settings, and add-ons.

Web developers might want a secondary profile for testing websites, apps, or other projects on different Firefox channels. For example, you might want to have some extensions installed for Web development, but not for general-purpose Web browsing. While using the Nightly channel, you may encounter some add-ons that have become temporarily incompatible with new API changes, until the add-on developer has a chance to update them. You can remove such add-ons from your profile for Nightly use while keeping them for use with other profiles.

For QA, testing, and bug triaging contributors, you may want to have multiple development versions of Firefox installed, each with its own profile. Creating new profiles for testing can keep you from losing your preferences, bookmarks, and history. It takes little time to set up a new profile, and once it is complete, all of your Firefox versions will update separately and can be run simultaneously.

Available browser development channels

There are four available browser channels, each at a different level of stability and development. The four channels are Release, Beta, Developer Edition, and Nightly. The Release channel is recommended for most users, as it is the "official release" channel. However, for those more adventurous, you can try one of the other three channels to see what is coming in Firefox and play around with emerging features. The Beta channel contains the features that are expected to be in the next release of Firefox and are in final stages of testing. Aurora contains experimental features, which are not yet at beta quality. Nightly contains the latest code from Firefox developers and is the least stable channel.

Third-party tools

In addition to the built-in Profile Manager and the external Profile Manager, there are a few third-party tools that make working with multiple profiles easy.

This list is by no means exhaustive. Please add any helpful tools you discover to the list!

Mac OS X

Profile management

Determining the profile while Firefox is running

To determine the profile of a currently-running Firefox instance in Windows, macOS or Linux,

  1. Type about:profiles into the browser URL search bar.
  2. The page presents a list of all of your profiles, each beginning with "Profile: " followed by its name.
  3. The one being run by this Firefox instance will include the bold text "This is the profile in use" For example, if you find that text beneath the entry for "Profile: Suzie", then you are running in a profile named Suzie.

Launching Firefox into a Desired Profile

Although it is possible in some cases to have multiple instances of Firefox running in different profiles, to avoid confusion, you might want to first exit/quit/terminate all running instances of Firefox, Firefox Developer Edition or Nightly. Then follow the instructions below, applicable to your operating system.

From profile manager inside Firefox

If you already have Firefox instance running, you can open another profile from the integrated profile manager on any platform:

  1. Type about:profiles into the browser URL search bar.
  2. Find the profile you want to use.
  3. Press the “Launch profile in new browser” button next to it.

Windows

Windows XP
  1. Click the Start button.
  2. Click "Run".

  3. Type firefox --new-instance--ProfileManager.

Windows Vista/7
  1. Click the Start button.
  2. Click the search bar at the bottom.

  3. Type firefox --new-instance --ProfileManager.

Windows 8/8.1/10
  1. Press "Windows + R" on your keyboard.
  2. Type firefox --new-instance --ProfileManager.

Linux

If Firefox is already included in your Linux distribution, or if you have installed Firefox with the package manager of your Linux distribution:

  1. Open a Terminal emulator or your Shell’s command prompt:
  2. Run firefox --new-instance --ProfileManager.

macOS

  1. Run the Terminal application, which is found in Applications/Utilities.
  2. Type or paste in the path to Firefox, followed by .app/Contents/MacOS/firefox.  For example, if Firefox is installed in the recommended location, you would enter /Applications/Firefox.app/Contents/MacOS/firefox.
  3. If you have the path to your desired profile handy, enter a space character, followed by -profile followed by another space character, followed by the full path to the profile folder you wish to launch into.  This will launch Firefox immediately.  Otherwise, enter a space character followed by --profilemanager.  This will present the Profile Manager window in which you can make your selection.
  4. Hit return.

Here is a complete example Terminal command from steps 2-3:

/Applications/Firefox.app/Contents/macOS/firefox -profile /Users/Suzie/Library/Application\ Support/Firefox/Profiles/r99d1z7c.default

If the Profile Manager window does not open, Firefox may have been running in the background, even though it was not visible. Close all instances of Firefox, or restart the computer, and then try again.

If you want to do this frequently and more easily, you may wish to create an Automator application, as explained in this tutorial.

Creating a profile

Creating a profile through the Profile Manager

These instructions should be the same for all operating systems.

  1. To start the Create Profile Wizard, click "Create Profile..." in the Profile Manager.
  2. Click Next and enter the name of the profile. Use a profile name that is descriptive, such as your personal name. This name is not exposed to the Internet.
  3. You can also choose where to store the profile on your computer. To select storage location, click Choose Folder....
  4. If you choose your folder location for the profile, select a new or empty folder. If you choose a folder that isn't empty, and you later remove the profile and choose the \"Delete Files\" option, everything inside that folder will be deleted.
  5. To create the new profile, click Finish.

Creating a profile through the Firefox browser

You can create a new Firefox profile directly from the browser.

  1. Type about:profiles into the browser URL search bar
  2. On the page, click Create a New Profile button
  3. Read the introduction, and click Next
  4. Enter a profile name for your new Profile. Use a profile name that is descriptive, such as your personal name. This name is not exposed to the Internet.
  5. Optionally, to change where the profile will be stored on your computer, click Choose Folder...
  6. To create the new profile, click Finish.

Deleting a profile

  1. In the Profile Manager, select the profile to remove, and click Delete Profile....
  2. Confirm that you wish to delete the profile:

Renaming a profile

  1. In the Profile Manager, select the profile you want to rename, and then click "Rename Profile".
  2. Enter a new name for the profile and click on OK.

Note: The folder containing the files for the profile is not renamed.

Options

Work offline

Choosing this option loads the selected profile, and starts Firefox offline. You can view previously viewed web pages, and experiment with your profile.

Don't ask at startup

If you have multiple profiles, Firefox prompts you for the profile to use each time you start Firefox. Select this option to allow Firefox to load the selected profile, without prompting at startup.

Note: To access other profiles after selecting this option, you must start the Profile Manager first.

Using the profiles

Windows

If you want to have the profile manager to pop up each time you start Firefox, so you can choose a profile, you will need to edit the "Target" of the launch icon. To do this:

  1. Right-click the icon and choose "Properties".
  2. When the properties dialog box pops up, you should see a "Target" text field that you can edit, and it should show the current file path.
  3. After the closing quote, add -ProfileManager.
  4. Click Ok.

Now whenever you double click that icon, the profile manager should appear, allowing you to choose which profile you'd like to use.

If you want individual icons to launch specific profiles, you will need to edit the "Target" of each icon. To do this:

  1. Right-click the icon and choose "Properties".
  2. When the properties dialog box pops up, you should see a "Target" text field that you can edit, and it should show the current file path.
  3. To permanently set a specific profile, add -p PROFILE_NAME to the target path, but outside of the quotes, replacing "PROFILE_NAME" with the actual profile name you chose.
  4. If you would also like to allow multiple instances of Firefox to run at the same time, add -no-remote after the profile name.

Once you are all done, click Ok. Do this for each icon you'd like to have a specific profile for. Once done, each one should automatically start with the specified profile.

Linux

There is no extremely straightforward way to create custom application launchers in Gnome 3 like there was in Gnome 2. The following tutorial will help get you going overall: Gnome 3 Custom application launcher. Once you get to the point of adding a new item, you can have the profile dialog show up every time or set the launcher to launch a specific profile.

If you want to have the profile manager to pop up each time you start Firefox, so you can choose a profile, you will need to set the command line for your new launcher.

  1. Set the "command" text field to target the executable file, likely "/usr/bin/firefox", and add the -p parameter.

If you want individual icons to launch specific profiles, you will need to set the command line for your new launcher. To do this:

  1. Set the "command" text field to target the executable file, likely "/usr/bin/firefox", and add the -p PROFILE_NAME parameter, replacing "PROFILE_NAME" with the specific profile.
  2. Repeat as necessary, for each additional profile you want to set.
  3. If you would also like to allow multiple instances of Firefox to run at the same time, add "-no-remote" after the profile name.

Mac OS X

You can find a useful tutorial to set up custom launchers here: Managing Multiple Firefox Profiles in OSX. Do note it's best to follow all steps in the "Creating the scripts" section, including the "edit Info.plist" step. Leave off the profile name if you want the profile selector to show up every time you launch.

Setting up multiple profiles for different Firefox channels

This section will be especially helpful if you are a developer, wanting to work with multiple channels, and each having their separate launcher.

Windows

In Windows, the Developer and Nightly builds get their own directory in the "Programs" folder, so you don't have to worry about where to store the downloaded files. However, all three will attempt to use the same profile by default. You won't want to keep this behavior, because the different channels have different levels of features. To set each launcher, follow the Windows instructions at Windows Launcher.

Linux

In Linux, things aren't as automatically set up. You will likely get a prompt to download a tar.bz2 file to extract from. Extract the files to a new directory, and use the new launcher instructions from here. The only change you will need to make is the command path. You will want to set it to the directory where you extracted the Firefox channel's tar.bz2 file, and the executable "firefox" file located within this directory. The remaining profile assignment methods will remain the same. You will want to, for sure, add the -no-remote part to the end of the command field, so that you could run multiple instances at the same time.

Mac OS X

You can find a useful tutorial to set up custom launchers here: Managing Multiple Firefox Profiles in OSX. Do note it's best to follow all steps in the "Creating the scripts" section, including the "edit Info.plist" step. Also, you'll want to change the path in the do shell script to point to the correct .app file for the Firefox channel you want to target.