How to Lock Firefox on Mac

Lock Firefox so it will not open without Touch ID or your password. Four steps, about a minute.

Lock Firefox on Mac, step by step

Download Cloak from trycloak.app and open it. Set up Touch ID or a password the first time it asks. There is no account.
Click the plus button under Locked apps, tick Firefox, and click Lock.
Quit Firefox if it is open.
Open Firefox again. Cloak now asks for Touch ID before it will launch.

Your Mac password works as a fallback by default. If other people know that password, open Cloak's Settings, turn off "Let my Mac password unlock Cloak", and set a Cloak password instead.

Who this is for

For people whose Firefox stays signed in to email, banking and social accounts. That is most of us. One person at your desk for a minute is enough.

What Screen Time can't do

Apple has no way to lock a single app on a Mac. The closest thing is Screen Time, which puts a daily time limit on Firefox. A limit is not a lock. Firefox opens normally until the time runs out, the Screen Time passcode is four digits, and anyone who knows it can click Ignore Limit for the rest of the day. It was built to manage screen time, not privacy. Cloak asks for Touch ID or your password every single time Firefox opens.

Why lock Firefox at all

Firefox keeps containers, saved passwords, and synced history that reveal far more about you than you would tell a stranger. Because a single unlocked window can hand a passer-by your logged-in sessions before you are back at your desk, Firefox is exactly the kind of app worth putting behind Touch ID.

Why a Mac-level lock beats Firefox's own settings

Browsers let you set a sync passphrase or a profile, but they keep you logged in and leave open tabs visible the moment the window is in front. Locking the whole app at the system level means the browser will not open, and your tabs will not be seen, until you pass Touch ID.

Frequently asked questions

Does locking Firefox with Cloak slow it down?

No. Cloak only steps in at launch to ask for Touch ID. Once Firefox is unlocked it runs exactly as it normally would, with no background overhead.

Will I still get Firefox notifications while it is locked?

Notification behaviour is controlled by macOS, not by Cloak. If you want Firefox alerts hidden too, pair the lock with hiding the app, or turn off previews for Firefox in System Settings under Notifications.

What happens if Touch ID is not available?

By default Cloak offers your Mac login password as a fallback, so you can still open Firefox on a Mac without a Touch ID sensor or if your finger is not recognised. If other people know your Mac password, you can turn that fallback off and use a separate Cloak password instead.

Can I lock Firefox with Screen Time instead?

Screen Time sets a time limit, not a lock. Firefox opens normally until the limit is reached, and the limit can be ignored for the day by anyone who knows the four-digit passcode. Cloak asks for Touch ID every time.

How to lock Firefox on your Mac