Firefox can save usernames and passwords that you use to access online services, such as banking and email websites in the Password Manager. If you share a computer with anyone, it is recommended that you use a master password in order to prevent another user to acces your usernames and passwords.

Setting a master password allow Firefox to encrypt your usernames and password using Triple Data Encryption Algorithm. After you have defined a master password, you will be prompted to enter it :

• the first time Firefox needs to access your passwords in order to connect you to a website, or you need to remember or remove a password,
• each time you want to display your passwords list in the Password Manager.

Defining a master password

By default, Firefox does not use master passwords to protect stored credentials. To define a master password:

1. In the Menu bar at the top of the screen, click Firefox and select Settings (select Preferences on older macOS versions).Click the menu button and select Settings.
2. Click the Security panel.
3. Check mark Use a master password.
   The Change Master Password dialog appears.
4. Enter your master password. The Password quality meter will indicate the difficulty of guessing the password. To create a quality password, your master password should include the following:
   • At least one capital letter.
   • One or more digits.
   • At least one non-alphanumeric character, such as the following: @ # $ % ^ & * ( ).
   • Also, remember to make your password something that is easy for you to remember, but difficult for others to guess to ensure that you, and only you, will be able to retrieve this secure information. For more information on choosing passwords, see Choose a strong password.
5. Enter the password a second time to confirm that you can enter it consistently.
6. To set the master password, click OK.
7. Close the Settings page. Any changes you've made will automatically be saved.

Removing the master password

If you don't need a master password, you can remove it at any time:

1. In the Menu bar at the top of the screen, click Firefox and select Settings (select Preferences on older macOS versions).Click the menu button and select Settings.
2. Click the Security panel.
3. Uncheck mark Use a master password. The Remove Master Password dialog will open.
4. Enter the current password to confirm you are authorized to remove it.
   • If you've forgotten your master password, see Reset your Primary Password if you've forgotten it.
5. Click Remove.
6. Click OK in the dialog that appears to confirm its removal.
7. Close the Settings page. Any changes you've made will automatically be saved.

Changing the master password

You can also change your master password at any time:

1. In the Menu bar at the top of the screen, click Firefox and select Settings (select Preferences on older macOS versions).Click the menu button and select Settings.
2. Click the Security panel.
3. Click Change Master Password.
4. Enter the current password to confirm you are authorized to change it.
   • If you've forgotten your master password, see Reset your Primary Password if you've forgotten it.
5. Enter the new master password twice.
   • Leaving the two fields empty removes your master password.
6. To accept the changed master password, click OK.
7. Close the Settings page. Any changes you've made will automatically be saved.

Based on information from Master password (mozillaZine KB)