Touch ID fails when external monitor attached

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Touch ID fails when external monitor attached

Using a 2020 M1-based MacBook Air, I find that Touch ID fails when I connect it to my external monitor via a Thunderbolt dock.

Setup: MacBook Air M1 running macOS 12.1 -> CalDigit TS3 Plus dock -> external monitor connected via DisplayPort. An Apple Magic Trackpad 2 is connect via Bluetooth, no external keyboards are used. The lid of the MacBook Air is open and I am using the laptop keyboard and Touch ID.

If I use the MacBook Air by itself, not connected to the dock, Touch ID works as expected 100% of the time.

Once I connect the MacBook Air to the dock in order to use the monitor, Touch ID simply fails 100% of the time and I must enter my password. This applies to all items, such as website logins or software updates.

As soon as I disconnect from the dock, Touch ID works again immediately. I understand how Touch ID might not like external keyboards, but this is not the case here. This issue has persisted across several OS updates.

Any ideas? Is the CalDigit TS3 Plus a problem here?

Posted on Dec 16, 2021 12:08 PM

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Answer 1

Top-ranking reply

Bradley Price1 Author

Level 1

69 points

Dec 21, 2021 4:47 PM in response to woodmeister50

Thanks, @woodmeister50. Update: I've tried simply connecting the monitor via an HDMI USB-C dongle. Touch ID works fine, and so it's something about the dock setup.

Further update: I've just tried using the dock, but instead of using DisplayPort I'm connecting the HDMI dongle to the CalDigit TS3+ via USB-C to drive the external monitor. Everything works. It's something about use of DisplayPort...

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Answer 2

Dec 22, 2021 10:25 AM in response to Bradley Price1

Final update: for reasons that shall forever remain shrouded in mystery, my setup now works. I can use my external monitor via my CalDigit TS3+ and Touch ID works on the MacBook Air keyboard.

The solution? I disconnected and reconnected the DisplayPort cable and power cycled the TS3+. That's all. I've love to think that this all makes sense, but whatever.

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Answer 3

Dec 16, 2021 12:56 PM in response to Bradley Price1

Try adding a new fingerprint when the dock is connected and see what happens.

FWIW, I am currently using an OWC Thunderbolt 4 dock and have encountered no such issues with the M1 MacBook Air sensor or my Magic Keyboard with TouchID.

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Answer 4

Dec 21, 2021 1:42 PM in response to Bradley Price1

You may want to check with CalDigit and see if they have seen any thing of the sort.

Personally, I have used the previously mentioned dock and USB-C docks and have not encountered an issue.

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Answer 5

Dec 21, 2021 10:18 AM in response to woodmeister50

Thanks, @woodmeister50. Unfortunately, that didn't work. My experience appears to be 100% consistent: connect the dock and monitor, Touch ID fails on everything. Disconnect dock and monitor, Touch ID works on everything, immediately.

I've doubled checked my CalDigit TS3+ and made sure the firmware and any drivers are 100% up to date, no change.

Next step I suppose is to bypass the TS3+ and try using the monitor through a simple USB dongle.

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Touch ID fails when external monitor attached

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