My second monitor always is in mirror mode

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Carrets Author

Level 1

6 points

My second monitor always is in mirror mode

My second monitor is always in mirror mode. There is no option in preferences to

"un-mirror". Holding down the option key does not give me the option to select the second monitor.

Posted on Apr 20, 2022 6:59 AM

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Answer 1

Top-ranking reply

BobHarris

Level 9

56,873 points

Apr 20, 2022 3:21 PM in response to Carrets

How are you connecting the 2 external monitors?

There is a difference between USB-C Docks and Thunderbolt 3 Docks.

A USB-C Dock will only receive a single DisplayPort signal over the USB cable. Without 3rd party DisplayLink software a USB-C Dock can only mirror the 2nd monitor to the first monitor, as it is only playing with a single DisplayPort signal.

A Thunderbolt 3 (or 4) Dock can drive as many monitors as it has ports and the Mac graphics subsystem can support. Typically a Thunderbolt 3 (or 4) Dock supports 2 external monitors.

So it is Very important that you be using a Thunderbolt 3 (or 4) dock, and not a USB-C dock.

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Answer 2

Carrets Author

Level 1

6 points

Apr 20, 2022 2:18 PM in response to lllaass

No, sadly, I don't. After start-up, if I unplug the LG monitor, and plug it back in, it no longer mirrors and I can have two separate displays and I see the options you have listed. But upon startup, the two displays are mirrored, the LG monitor is greyed out, the option key held down does not give me any other options for night shift.

This all used to work perfectly until a few upgrades ago.

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Answer 3

lllaass

Level 10

210,513 points

Apr 20, 2022 7:24 AM in response to Carrets

You do not have this option?

when you click on Use as:

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My second monitor always is in mirror mode

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