Firefox’s Primary Password adds protection to saved logins on that installation. Decide how you will remember or securely retain it before enabling it. Mozilla warns that resetting a forgotten Primary Password removes the saved usernames and passwords; reset is not a way to reveal them.

Set the local protection deliberately

Open Firefox’s Passwords menu and its settings. Depending on the version, the option appears as Use a Primary Password or Set primary password under additional protections. Create a unique password and confirm it in the dialog. Store any recovery reference somewhere appropriately protected outside the Firefox password store it unlocks.

Mozilla describes the Primary Password as local to a profile and device. Setting it on the office computer does not establish the same protection on a home computer or another Firefox profile. Make an inventory of the installations where saved business logins are actually used.

Close Firefox after saving browser work, reopen it and request access to a harmless saved login. Confirm that the expected Primary Password prompt appears and that you can unlock the entry. Mozilla explains that Firefox normally asks once per session when it needs the stored passwords, rather than for every page you visit.

Keep other access controls in place

Do not treat the feature as a lock for every browser activity. A person using your already unlocked session may still see open pages and their content. Continue using the operating system’s lock screen and separate user accounts where different people need private workspaces.

Keep website recovery methods current independently of this local password. If the Primary Password is forgotten, stop before selecting a reset instruction and establish which account credentials can be recovered through the services themselves.

The acceptance check is specific: the saved-login store requests the local protection after a new browser session, you can unlock it, and you understand the reset consequence. It is not a claim that the entire computer is inaccessible to another user.

Sources: Mozilla Support, Mozilla Support.