Posteo Help Help categories Article

This article is tagged with: FirefoxMailvelopeMac

How do I create and use a Posteo Firefox profile in Mac OS?

With Firefox profiles, you can use multiple Firefox environments on your Mac. For example, you can separate your secure email communication with Mailvelope from other add-ons.

In this help article you will learn how to open and set up the Firefox profile manager on your Mac, and how to use two Firefox profiles simultaneously.

Important: Also note the additional security recommendations at the end of this article.

How to open Firefox profile manager on Mac OS

Using the Firefox profile manager you can create new profiles, select a profile to start with or deactivate the profile manager at a later time.

  1. Open the Finder
  2. In the menu, click Go
  3. Click Utilities

Open Finder, click "Go" then "Utilities"

  1. Open the Terminal program by double-clicking
  2. In Terminal, enter the following command: /Applications/Firefox.app/Contents/MacOS/firefox-bin -P
  3. Confirm your entry with the Enter key

Open Terminal and enter the command "/Applications/Firefox.app/Contents/MacOS/firefox-bin -P". Confirm using the enter key.

You have now opened the Firefox profile manager.

How to create a Posteo profile in Firefox

You will now find out how to create a separate Posteo profile and switch between your existing profile and Posteo.

  1. In the Firefox profile manager, click Create Profile…
  2. Click Continue
  3. Enter a name for the new profile, such as Posteo, for example
  4. Complete the setup by clicking Done

How to start a profile in the profile manager

  1. Select a profile such as your Posteo profile, for example, by clicking it
  2. Remove the tick next to "Use the selected profile without asking at startup".
  3. Click Start Firefox

Select a Firefox profile, remove the tick next to "Use the selected profile without asking at startup" and click "Start Firefox"

From now on, the profile manager will open automatically each time you start Firefox. You can then decide which profile you would like to use.

How to switch between Firefox profiles

If you would like to switch from one profile to another, you can simply close Firefox from the menu under Firefox and then Quit Firefox. Then simply start Firefox once again to select a different profile.

Additional security recommendations for the use of Mailvelope in Firefox

Under specific circumstances, Firefox’s security architecture allows attackers to access a user’s private keys via compromised add-ons. Please also read our blog post from the 4th of May, 2017. Using an independent Firefox profile for Mailvelope only minimises the risk if you also adhere to the following advice:

  • Do not install any additional add-ons in the newly-created browser profile
  • Use the Firefox profile exclusively for encrypted Mailvelope communication: Access your email provider’s webmail interface only and never visit other websites
  • In addition, choose a password for your PGP key that is as secure as possible
  • Be careful not to accidentally install any add-ons via phishing, via which you could be attacked

Due to the problems with the Firefox architecture, we additionally recommend:

  • Restrict the use of add-ons in the Firefox browser to a minimum, until Mozilla has updated the architecture
  • You can further protect yourself from potential attackers by setting up an additional user on your operating system for end-to-end encrypted communication

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