After update from 10.15.3 to 10.15.4 external displays doesn't work via docking station

Hi,

can "Kei Kim" and/or "WenzlikCZ" or any other post me your case number?

I wanna give them to the Apple supporter who proceed my case, but he told me not to believe what other post in the internet 🤔. But when I can tell him a case number with the same problem, maybe he believe me, that it is no local problem of my setup.

Thanks.

By the way, the support told me to reinstall Mac OS and I could not believe, but... "No Signal" 😂

Please report this issue to the Apple support assistant. That might be a much better way to inform Apple about this issue. You can visit this website (https://getsupport.apple.com/?caller=psp&PRKEYS=PL107 ) and make a case. This forum is not a good place to let them know. 

My case number is 101053644789. If anyone had reported the case number, please share those case numbers here as well. Collectively, we can show that it’s not a mishap or this-Mac-only problem. 

My case number is 101053644789.

Let’s collect similar case numbers so that Apple can perceive that this problem is worth solving. I will let the Apple staff know your case number as well so that he can comment on the report that he has just sent.

For anyone who likes to report this issue to Apple via care support, let them know similar case numbers:

* MBP 16 inch+Dell UP2414Q(4k 60hz) dp1.2 to usb c broken (@Kei Kim case 101053644789)

* MBP 16 inch+Icy box DK-2403-C docking station (@Weber_NRW case 101056259745)

And also please share your case number & setup. 

Thanks.

Oh dear - mine was my fault. I had taken it all apart a few days before for boring reasons and it turns out there are two thunderbolt ports on the back but one of them is low power and one high. Guess which one I plugged in :(

User error. All fine now.

As I've mentioned before, resetting the SMC works for me too, but I have noticed another issue after update - when I plug in to my hub (to USB 3.0) additional device, like iPhone, the iPhone is charging, but the MacBook is not charging anymore. When I unplugging the iPhone, the Macbook starts charging again.

All of these issues looks like some limitation in voltage / current - I think that's why some of you had some limitations in resolution or frequency on external screens also.

Just updated as well and my external display via USB-C to Displayport isn't working when I connect it to the 2nd USB-C port on my 2019 13" MacBook Pro. Only works when I connect it to the first USB-C port. I'm on the back MacBook Pro with two ports.

Update: I tried resetting the SMC and it has fixed the issue, both ports work again for the external monitor.

I just updated to 10.15.4 and I have a 4K LG 27UL850 display which stopped showing 4k picture and it's showing HDR... terrible picture. Tried deleting profiles, resetting my display, restarting my MacBook pro, etc. Nothing worked. :/

Hello

I'm using a 2018 Mac mini with two HDMI display : one directly on the HDMI port, the other on a USB-C/HDMI adapter.

After the 10.15.4 update, the adapter is not recognized anymore, and I can use only one screen. Each screen work alone and the adapter is fully operational on another computer. Hope this will get fixed soon, I need my second screen since I'm working from home now...

I'm having the same issue, after I updated my MacOS my Dock Dell D6000 stoped working, even for charging, in the battery menu says, 'its not charging', I've already reset my MacBook to factory and make a clean installation for tests and the same happens.

A strange thing happen today : waking up my Mac from sleep, both screen are again functional. I changed nothing. It's frustrating to not know what's happening, but I'm glad I can use my setup as intended 😊

same issue with my MBP 2019. working perfectly fine previously but no power to my docking after update. waited a long time to talk to Apple engineered, tried SCM and reinstalling catalina 10.15.4, none of them work. weird enough, tried put my dock upside down, it's powered up and working. but that's not solving the issue fundmentally, apple needs to get it fix asap

Yes this worked thank goodness - I had Thunderbolt Display and was using the original cord with adapter to USB-C for the monitor and the other USB-C port for powering my MacBook Pro 13” 2019. Nothing worked except when I just switched USB-C ports the monitor came back to life - and Ethernet “flows” through it to my MacBook Pro. Yay!!

I'm now having the same issue. New MacBook Air 2019, was working fine with D6000 but after updating today it's not allowing me to connect to the monitors.. I don't know how to do a simple downgrade back to 10.15.3 - can anyone help? I've tried everyone's suggestions already in this thread and nothing has helped. :-(

I have been trying to find a way to do this too. The best options I have seen are doing a restore from a Time Machine Backup before the update, which is a royal pain. The other option is to completely wipe the computer and install a 10.15.3 version... even less fun.