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Khun Ron Author

Level 1

8 points

Macbook Pro 2019 Not Recognizing External Monitors

My setup shown below was working 2 days ago (Sep 14, 2020). I woke up yesterday and my MBP was shut down. I'm assuming there was an OS update and my external monitor was no longer recognized in the Displays tab of System Preferences. The LG On-Screen Control app was also not recognizing it.

Setup: 13" MBP w/ Touchbar, connected to an LG 34UM69G-B monitor using a Henge Stone dock and HDMI cable.

Since this happened I have tried all the suggestions I've found online like unplugging cables, restarting MBP and monitor, resetting NVRAM and SMC, changing cables, etc.

I am working from home and had my two laptops connected to the monitor using a KVM switch. I've disconnected the switch and the Windoze laptop connects directly to the monitor with no problem.

I also have a secondary monitor which I've connected via an HDMI cable and also tried connecting my iPad Pro directly to the monitor via USB-C and nothing.

Was there a recent OS update which has messed up anyone else's setup? Any other recommendations?

Posted on Sep 16, 2020 6:12 AM

Top-ranking reply

Sharhari

Level 5

6,293 points

Posted on Sep 16, 2020 7:04 AM

Last macOS security update was on 12 Aug 2020. Below link for ref.

Apple security updates - Apple Support

Also you can check the software installation by date in system information.

> (hold option) System Information… >

In Software section Installations you will find info.

To start troubleshooting connect one Monitor at time directly to MBP and see if it works.

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Macbook Pro 2019 Not Recognizing External Monitors

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