macOS Sierra: The Missing Manual

Touch ID

As you could probably guess, this panel appears only if your laptop has a Touch Bar and Touch ID fingerprint sensor.

This sensor is built right into the power button (clever!). It reads your finger at any angle. It can’t be faked out by a plastic finger or even a chopped-off human finger. You can teach it to recognize up to five different fingerprints. They can be a few of your fingers or, for example, you could teach it one finger each for five family members.

Before you can use your fingertip as a password, though, you have to teach the Mac to recognize it, and here’s where you do it:

1. Create a password.

   That’s right: You can’t use a fingerprint instead of a password; you can only use a fingerprint in addition to one. You’ll still need a password from time to time to keep the Mac’s security tight. For example, you need to enter your password if you can’t make your fingerprint work (maybe it got encased in acrylic in a hideous crafts accident).

   So open System Preferences→Accounts and create a password (Phase 2: Name, Password, and Status), if you haven’t already.

2. Teach a fingerprint.

   Click the “Add a fingerprint” button.

   Start by entering your account password, to prove that you’re not a sinister spy. Click OK.

   Now place the finger you want to train onto the power button—your index finger is the most logical candidate. You’re asked to touch it to the power button over and over, maybe six times. Each time, the gray lines of the onscreen fingerprint darken a little more (Figure 10-20 ...