After update from 10.15.3 to 10.15.4, external displays doesn't work—via display port 1.2 to USB-C cable

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Level 1

11 points

After update from 10.15.3 to 10.15.4, external displays doesn't work—via display port 1.2 to USB-C cable

I've updated my Macbook Pro 16inch's OS to 10.15.4. My mac is connected with the external monitor, Dell UP2414 q via Display Port cable.

After the update, the external monitor doesn't display any image.It's weird as the system can recognize the monitor, but nothing appears on the screen. The screen goes to black and turns on repeatedly OR simply turns off.

When I limit the bandwidth to only display port 1.1a, the monitor displays(only at 30hz, which no one can use... )

I suspect this must be a relevant problem to the HDR or display port related update.

MacBook

Posted on Mar 27, 2020 12:37 AM

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Answer 1

BreeZee_17

Community Specialist

Mar 28, 2020 10:25 AM in response to Kei Kim

Hi Kei Kim,

Thanks for using Apple Support Communities! I see you're having an issue with your external monitor and I'd like to do what I can to help out.

Have you restarted your Mac and monitor since noticing this issue? If not, go ahead and do that, as a restart can resolve unusual issues.

If you're still having the issue, follow the steps in this article: Get help with video issues on external displays connected to your Mac

Take care!

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Answer 2

raina_b22

Community Specialist

Mar 28, 2020 1:23 PM in response to Kei Kim

Hey Kei Kim,

Thanks for the reply and additional information.

I'm sorry, this is a user forum. You'll need to either contact the Apple Support person who is handling your case, or call back to Apple Support. Contact Apple for support and service

Thanks and enjoy your day!

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Answer 3

Kei Kim Author

Level 1

11 points

Mar 28, 2020 10:41 AM in response to BreeZee_17

Hi,

I've done lots of things, of course including reboot, SMC reset, NVRAM reset, removing some plist files :)

I also requested support from Apple and got some remote assistance from Apple's staff, but they couldn't solve the issue. Now they are also investigating the problem. Anyway, none of the above solved my problem.

For me, the problem was very clear, as it was fine 10 minutes before the update, but the monitor stopped working as soon as the update was finished. After trying several TODO things, the Apple assistant understood what was happening and run a couple of programs to collect relevant logs on my Mac.

I've been Apple fans for many years and have been using MacBooks for those years, but this was the worst experience I've ever encountered. For me, this update wasn't actually an update, but a horrible disaster—the fact that my Mac is the newest one didn't help much.

The reason why I'm also writing here is to somehow escalate the problem with little hope of the actual Apple OS developer can start digging into the problem. The same monitor is working fine with iMac 27 inch model which runs 10.15.3

Now, because of the problem, I cannot use my external monitor, so I'm only using my laptop's screen. I hope Apple team can solve the issue and let me use my external monitor again.

Are you Apple staff? Can you forward this problem to the relevant team members?

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Answer 4

Apr 25, 2020 11:01 PM in response to BreeZee_17

I have exactly the same problem.

I have noticed my external monitor becomes 30hz right after I upgrade to 10.15.4.

The magic mouse becomes very laggy, so this is a terrible experience.

Still have no idea how to fix this.

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After update from 10.15.3 to 10.15.4, external displays doesn't work—via display port 1.2 to USB-C cable

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