I’ve tried using various third-party apps to unlock my iMac using my Apple Watch (MacID, Knock, etc.) but I never found a solution that worked consistently and that just got out of the way. But Apple’s official unlock with Apple Watch feature — new in MacOS Sierra — works GREAT (though I did run into a minor glitch during setup which I’ll tell you how to fix below).
For me, unlocking my Mac with this new feature usually takes about two seconds (but occasionally it can take closer to four). That’s on a fully-maxed 2015 27″ Retina iMac. Instead of a password box on the lock screen you’ll see your user image with a message that says unlocking with Apple Watch. On your Watch you’ll also get a Mac Unlocked notification.
All said getting the settings right took about three minutes from start to finish.
To setup your Mac to unlock with your Apple Watch you just need to do two things: 1.) setup and enable two-factor authentication (if you haven’t already) and then check the appropriate box in your Mac’s security settings.
1.) Enabling Two-Factor Authentication
To setup or enable two-factor authentication I would recommend doing everything from within your Mac’s settings (though you can do it elsewhere). Click the Apple icon in the top left corner of your screen, click iCloud and then select Security. From here, setup and enable two-factor authentication.
2.) Allow Your Apple Watch to Unlock Your Mac
Once two-factor authentication is setup goto Security & Privacy in your Mac’s settings (again by clicking on the Apple icon in the top left of your screen). Then click General and check the “Allow your Apple Watch to unlock your Mac” box.
Beating the “Mac Unable to Communicate” Glitch
That should be it — you should be all setup. For me, though, I couldn’t check the box at first — I kept getting an error message saying “Your Mac was unable to communicate with your Apple Watch.” Fortunately the fix was very simple. All it took was going into Settings, General, Handoff on my iPhone and toggling the switch off and then back on. After that everything worked and I’ve had no trouble since.
This is a super-convenient way to get into my Mac. If you work in a busy office, out of a coffee shop or other public space or have kids running around your house ...