If you share your computer with other people, you may want to prevent them to change your personal settings such as your bookmarks and view your stored passwords. This article describes basic protections to take.

Use separate user accounts

You can create separate accounts for each person that will be using your computer. This allows each user to have their own customization such as the wallpaper, visual style and their own document folders such as the Firefox profile that stores your bookmarks, Sync connection status, stored passwords and other personal settings. Each person accesses his or her user account with a username and password.

To create a user account:

For more information on choosing passwords, see Choose a strong password.

Lock your computer

When you leave your computer, you should lock the screen to prevent other people from using your desktop and accessing your files. You will still be logged in and all your applications will keep running, but you will have to enter your password to use your computer again. You can lock the screen manually, but you can also have the screen lock automatically.

Protect your Firefox passwords by a master password

You can set a master password in Firefox to protect against adding, removing and viewing your passwords by someone else.

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.
4. The Change Master Password dialog appears. As you enter your master password, the Password quality meter indicates 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. The password must be entered twice to confirm that you can enter it consistently.
6. To set the master password, click OK.
7. The master password is defined.

Changing or removing the master password

You can change or remove 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.
   • To remove the master password, leave the new master password fields empty.
6. To accept the changed master password, click OK.
7. The master password is changed.

Based on information from Master password (mozillaZine KB)