How to run Firefox with a clean profile

You can run Firefox with new another profile, without losing your daily profile. Researching on a clean profile will help you to make minimum conditions to reproduce the problem clear.

If you use Firefox 67 and later, you just need to install Firefox to another location.

For example, assume that your regular Firefox is installed into C:\Program Files\Mozilla Firefox on your Windows. Then you need to start Firefox installer and change the installed location to different place like C:\Program Files\Mozilla Firefox Debug. After that, launch the newly installed Firefox, for example double click the executable file C:\Program Files\Mozilla Firefox Debug\firefox.exe. Then you'll see a new Firefox instance running with a new clean profile. You don't need to stop running of Firefox with your ordinal profile. The another instance of Firefox installed to another location can be started in parallel even if you already run your ordinal Firefox.

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If you don't want to install Firefox to multiple locations, there is one more legacy method to run Firefox with clean profile in parallel.

Firefox accepts following two command line options to do it:

• -profile: allows you to specify the location of the profile to be used. Even if there is no such folder, Firefox automatically creates it.
• -no-remote: allows you to start the Firefox separately from the running Firefox with your default profile.

On Windows

1. Create a shortcut to the file firefox.exe. Generally it exists at the location C:\Program Files\Mozilla Firefox\firefox.exe.
2. Open the property dialog of the shortcut you created at the step 1.
3. At the linked location field, add parameters -no-remote -profile "(path to a blank folder)". For example, it will be "C:\Program Files\Mozilla Firefox\firefox.exe" -no-remote -profile "%temp%\fxprofile"

On Linux

1. Open a terminal window.
2. Create a blank directory, like: mkdir -p /tmp/fxprofile
3. Run Firefox with options -no-remote -profile "(path to a blank folder)". For example, the command line will be firefox -no-remote -profile /tmp/fxprofile.

On macOS

1. Open a terminal window.
2. Create a blank directory, like: mkdir -p /tmp/fxprofile
3. Run Firefox with options -no-remote -profile "(path to a blank folder)". For example, the command line will be /Applications/Firefox.app/Contents/MacOS/firefox -no-remote -profile /tmp/fxprofile.