macOS Sierra: Troubleshooting Mac Auto Unlock With Apple Watch

In macOS Sierra Apple added a feature that lets you use your Apple Watch to automatically unlock your Mac. But Mac Geek Gab listener John was having trouble with Mac auto unlock. Here’s what he figured out.

Device Requirements

In order to use this feature your devices need to meet a couple of requirements:

  • Apple Watch running watchOS 3 or later
  • Mid-2013 or newer Mac running macOS Sierra 10.2 or newer

You also need to set up two-factor authentication for your Apple ID. The Mac Observer has a guide to set it up. Make sure you sign into your Watch and Mac with the same ID. Next, Apple says that your Mac can’t be using Internet Sharing or screen sharing. To make sure, go to System Preferences > Sharing.

So here’s what happened with John. To use Mac auto unlock both Bluetooth and Wi-Fi need to be turned on, and he forgot to do this.

Screenshot of Wi-Fi settings. If you have trouble with Mac auto unlock, check the signal-to-noise ratio.

Other Troubleshooting

Other Mac Geek Gab listeners wrote in with some solutions as well, in case you still can’t use auto unlock, such as restoring the watch from iCloud. Another tip that is a bit more involved is checking the signal-to-noise ratio between your watch and Mac.

Listener Dominic said that he used software called iStumbler on his Mac Mini. He found that the signal-to-noise ratio on his 2.4GHz Wi-Fi was only 12dB. This is usable but should be better. It turns out that an external white-box USB3 SSD enclosure was the problem.

After he moved the enclosure away from the Mini and away from the Wi-Fi antennae, his signal-to-noise ratio increased to a much better 36dB and allowed Mac auto unlock to work perfectly.

To find your signal-to-noise ratio, option-click the Wi-Fi icon in the menu bar. Look for the RSSI number, which is the decibel level.

One thought on “macOS Sierra: Troubleshooting Mac Auto Unlock With Apple Watch

  • There was a build or 2 of 10.13.4 beta that watch unlock stopped working for me. The Mac knew it was trying to unlock with Watch, told me to put in password to unlock with Watch in future, but the Settings option to Unlock With Apple Watch was actually missing from the settings screen… and paused before putting up the password field, as if it was ‘doing something’, then put up the password field without comment.

    The latest build 17E170c restored the functionality, without me having to do anything.

    Personally I object to 2 factor authentication (there are plenty of articles why it’s not good to link to your phone) and actually abandoned Watch Unlock setup a couple of times before I went down the irreversible road of Apple’s poor choice for ‘added security’.

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