The option for unlocking your Mac with Apple Watch is in Security & Privacy settings Now restart your Mac and Apple Watch. On your Mac, go to the Apple menu and choose Restart. On your Apple Watch.
How to enable Auto Unlock on Apple Watch Make sure your Apple Watch is running watchOS 3 or higher. You can also find available firmware update by going to the Watch app (on your iPhone) General Software Update. Turn on Passcode for your watch.
How to enable Auto Unlock on your Mac Click on the Apple icon in the upper left corner of your screen. Select System Preferences from the drop-down menu. Source: iMore Click on Security & Privacy. Click on General. Tick the box to Use your Apple Watch to unlock apps and your Mac. Auto Unlock will.