Dual external monitors Display Settings only showing one

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Level 1

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Dual external monitors Display Settings only showing one

I've been using this setup for a long time with no issue: two old Dell external monitors (read: not 4k), one connected with HDMI (vertical) and one with USB-C (horizontal).

Today I'm only able to have one fully working at a time, but it's weird.

Plug in USB-C first, fine.
Add HDMI: USB-C monitor is still displaying my desktop but I can't navigate to it, and it is not in my Display Settings. HDMI monitor works.

Plug in HDMI first, almost fine, but shows up horizontal (supposed to be vertical).
Add USB-C monitor: the HDMI one flips to the correct vertical orientation, and USB-C is on but black and not showing in Display Settings.

Ideas? I've tried Detect Displays, and nothing happens. Restarted, unplugged everything, replugged.

MacBook Pro (M3 Pro, 2023)

Posted on Nov 3, 2025 10:08 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

139,559 points

Nov 3, 2025 1:43 PM in response to rlb26

For MacOS 12 Monterey and some later versions, some users got relief by deleting some preferences files, then Restarting:

Library/Preferences/com.apple.windowserver

-AND-

~/Library/Preferences/com.apple.windowserver.<UUID>.plist -OR-

~/Library/Preferences/ByHost/com.apple.windowserver.<UUID>.plist

-- where [~] tilde is an active abbreviation for "current user"

-- and <UUID> is a string of hexadecimal numbers unique to your system, grouped as 8-4-4-4-8 hexadecimal digits

Restart REQUIRED after these deletions.

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