Mac Mini still detects monitor when it is unplugged or turned off

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Mac Mini still detects monitor when it is unplugged or turned off

I have a Mac mini (2018) that continues to detect an HDMI connected monitor even after the monitor has been powered off/unplugged from power. When I unplug the HDMI cord it does remove it from my display arrangement, but this isn't helpful; I don't want to unplug my HDMI cord from my second monitor when I want to just focus on my main display.

I have already tried the "detect displays" button, deleting the profile, and have rebooted many times.

Editing to add that I don't think this is a residual power issue, as this spans multiple hours - even days - until the HDMI cord is disconnected the mac thinks the monitor is in use.

Mac mini 2018 or later

Posted on May 26, 2020 11:57 AM

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Answer 1

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QuickPost

Level 10

103,335 points

May 26, 2020 1:50 PM in response to kkozy

Hello,

Try running the following tests:

How to reset the System Management Controller (SMC) on your Mac - Apple Support

Reset NVRAM or PRAM on your Mac - Apple Support

How to use Apple Hardware Test on your Mac - Apple Support

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Answer 2

kkozy Author

Level 1

9 points

May 27, 2020 5:31 AM in response to Malcolm J. Rayfield

I have never experienced this with a Mac - even this Mac Mini with other display sources. To be clear; the HDMI display persists even after the display has been turned off, or unplugged. Turning on mirroring changes nothing - the computer still believes the display to be on and active though it has no power.

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Answer 3

May 27, 2020 10:41 AM in response to kkozy

Both my current 2018 Mac mini, and my previous 2008 Mac Pro would show the second (HDMI TV) display in Displays preference even if i was turned off. With the "Gather Windows" button, you could see its preference and change its settings. The cursor and windows could be moved off the main display over to where the other display would show them, if it was on.

Turning on Mirroring does not make the second display go a way, but it prevents the cursor and windows going over to it, and if you open an app that previously was using that display, its window will come back to the main display.

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Answer 4

May 26, 2020 11:02 PM in response to kkozy

This is normal behavior. To disable the HDMI display, turn on mirroring.

In Displays system preference, you can enable "Show mirroring options in the menu bar" to make it easy.

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Mac Mini still detects monitor when it is unplugged or turned off

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