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Question: LG 34WK650 - black screen on MacBookPro9,2

Hello everyone!

My LG 34WK650 isn't working with MacBookPro9,2 (MBP 13" mid 2012, MacOS 10.13.4, SMC 2.2f44).

I connected monitor using mDP-DP cable, and system recognize it correctly, I can choose resolution and refresh rate, but screen keep black/no signal. When I connect another monitor - Dell U3415W, using the same mDP-DP connection, it's working great on higher than LG resolution (3440x1440). So I suppose, that MacBookPro hardware can work with 2560x1080 resolution with LG monitor.

LG monitor work correctly on MacBook Air 2017 (MacOS 10.13.4), without any problems and special settings.

Please help me with this 🙂

MacBook Pro, macOS High Sierra (10.13.4)

Posted on


May 25, 2018 2:27 PM in response to avatatpl In response to avatatpl

Hello avatatpl,

Thank you for using Apple Support Communities.

I see that you are having an issue with the LG display connected to your MacBook Pro. I would suggest taking a look at the following support article to sort out what might be going on:

Get help with video issues on external displays connected to your Mac

Best regards.

May 25, 2018 2:27 PM

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May 25, 2018 4:17 PM in response to sterling r In response to sterling r


I have some progress in this case:

After few minutes talk with senior support specialist, we do nothing.. 😟 I was sure, that it's MacOS related problem and booted up Ubuntu 18.04 - display still won't work on mentioned MacBook Pro mid 2012.

Then I reminded, that I have second MacBook Pro Early 2011 (more than one year older than previous MBP!). I moved my drive from first to second MBP and LG monitor start working correctly! 😉

So we have success, but this monitor still not works on MBP Mid 2012. Do you have any idea what's wrong with it?

May 25, 2018 4:17 PM

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Question: LG 34WK650 - black screen on MacBookPro9,2