MacBook stopped recognizing external monitor after shutdown

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Level 1

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MacBook stopped recognizing external monitor after shutdown

I am using KOORUI external monitor. after about 6 months display was flickering and I replaced the connector cord with a better quality one. Since then it has worked perfectly. I had to shut down MacBook Pro yesterday, and since then, it will not recognize the monitor at startup. There was no indication of problems.

Things I have tried.

Shut down/disconnect monitor and MacBook. Restart.

change cord to different Mac connector port (usb3)

Installed DisplayLink Manager. Nothing changed.

Tested Sidecar (working)

Any thoughts would be appreciated.

MacBook Pro (M4 Pro, 2024)

Posted on Mar 7, 2026 7:25 AM

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Answer 1

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neuroanatomist

Level 9

56,829 points

Mar 7, 2026 7:33 AM in response to Atarapa

Atarapa wrote:

Installed DisplayLink Manager. Nothing changed.

Are you using a hub/dock that relies on DisplayLink? If so, it may be that your Mac updated macOS to the current version and there is a compatibility issue with DisplayLink. In that case, you will need to wait for updated drivers or directly connect the display to your Mac.

FYI, the normal sequence of connecting a display is to have your Mac on, have the display on, and then plug the display into your Mac.

After performing that sequence of steps, go to System Settings > Displays, then hold down the Option key and click Detect Displays (that button is Night Shift without the Option key pressed). Is your display found?

As you can see from my screenshot, my external display is working fine on macOS 26.3.1.

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