What if I can't unlock with my face?
Your camera broke. You're wearing something that covers your face. You want someone else to use your computer while you're away. Or maybe face recognition just isn't working for some reason. You're not locked out. Shield uses the same lock screen as your operating system, so you can always unlock with your system password.
You can always unlock with your password
When Shield locks your screen, it uses its own lock screen. It's not the standard Windows or Mac lock (unless you choose that option in settings). But you can always type your system password to unlock. Shield accepts the same password you use to log in to your Windows or Mac account.
How it works
Shield has its own lock screen that activates when you step away. While locked, keyboard shortcuts and system keys are blocked so nobody can bypass the lock. The only ways to unlock are your face (automatic) or your system password (manual).
If you prefer, you can configure Shield to use the standard operating system lock screen instead. In that case, all your normal unlock methods work: password, PIN, fingerprint, Windows Hello, Touch ID, Apple Watch, or any other method you have configured.
Either way, you always have password access. Shield's face recognition is an automatic convenience that unlocks your computer when it sees you. But if face recognition doesn't work for any reason, your password is always there as a fallback.
Common scenarios
Your camera stopped working. Maybe a hardware issue, maybe a driver problem, maybe you accidentally covered it with a sticker. Shield can't see your face, so it can't unlock automatically. No problem. Type your password and you're in. Fix the camera when you have time.
You're wearing a mask or face covering. If Shield can't recognize your face because it's covered, just type your password. Once you remove the covering, face unlock will work again automatically.
You need someone else to use your computer. A colleague needs to check something on your laptop while you're in a meeting. You're on the phone and can't sit down in front of the camera. Just give them your password. They type it in and the computer unlocks, exactly like it would without Shield.
You're in very dark lighting. If the camera can't see your face because the room is too dark, type your password. Shield will resume face recognition once there's enough light.
Face recognition isn't working well. Maybe you changed your appearance significantly, or the camera quality is too low. You can always fall back to your password and then re-enroll your face in Shield's settings.
Re-enrolling your face
If face recognition consistently isn't working well, you can reset your face enrollment and start fresh. Open Shield's settings and choose to re-enroll. The app will ask you to look at the camera from a few angles again, just like the first time.
To re-enroll, you need to enter your system password first. This is a security measure. It ensures that only you (the person who knows the computer's password) can change whose face unlocks the computer. Nobody else can re-enroll a different face without your system password.
Why the system password is required
Re-enrollment means changing whose face can unlock the computer. This is a critical security action. Requiring the system password ensures that someone can't sit in front of your laptop and register their own face while you're away. Only someone who already has access to the computer (through the password) can change the face enrollment.
Shield adds, it doesn't replace
The key thing to understand is that Shield adds an automatic layer of protection on top of your existing setup. Your system password always works as a way to unlock. Shield simply adds two things: automatic locking when you leave, and automatic unlocking when you return.
If the automatic part ever fails, your password is always available. You are never locked out of your own computer.
Summary
Shield locks your screen with its own secure lock. You can always unlock with your Windows or Mac password. Face recognition is an automatic convenience, not the only way in. If you need to re-enroll your face, you'll need your system password for security. You are never locked out.