How to resolve flickering and unusable external monitors with the new MacBook Pro 16"? Displays have worked with previous MacBook Pros.

Thanks for the help... the LG display software has no settings that change sleep or port priority functions that I see. Regarding the detect display button on the MacBook Pro. Where is that button? I've seen that suggestion before but can't find it. When the display does not wake, the the MBP does not usually wake either. The MBP display seems to flicker and not show the desktop. It usually requires a restart.

Be sure Apple support knows about your issue. They can run through the easy solutions with you. If not resolved, do not let it drop, ask them to file a bug report.

You can use the "Contact Support" link on the top right of every forum page.

I have the same problem (ethernet) with WD15 (mine is 2018 air, 10.15.2). The only solution now is to reboot the mac. It only the first time you connect the device. Once you disconnect it, you have to reboot it no matter what. (you can try to switch off/on. ) I guess catalina is the problem.

when you turn off the ethernet and turn it on again, it somehow works but very very slow.

(you can try yourself "sudo ifconfig XXX down/up", XXX is id of your device)

Found a work around for internet, for now. SystemPrefences>Network>Thunderbolt Bridge>Setting Wheel>Manage Virtual Interfaces>Thunderbolt Bridge>Edit(Pencil Icon)>Enable "USB 10/100/1000 LAN">Hit done exit all the way. Turn off Wi-fi to confirm you are able to access internet through WD15.

I have this issue with multiple setups; I run an IOGEAR dock that pushes 100 Watts and I still have this issue. I have an ASUS portable monitor that worked fine on my MacBook 2016 without issue but new MacBook Pro 16 inch can't run it. There is a driver issue. Ive also noticed that when I use the Apple USB-C dongle my MacBook Pro stops charging when it goes to sleep.

I am having this same issue with a variety or variations that worked perfectly fine with my other MacBook. First I noticed that when I plug in my dock I got flickering; I thought maybe it was a cable or dock issue as the dock gets relatively heavy use. I tried a variety of cables as well as an Apple USB-C dongle and had the same issue with the ports on the left side of my 16 inch Pro. I then switched to the right side of the unit and got it to work occasionally. Sometimes if the computer is sleeping it won't wake up or the external display won't activate. Yesterday I was working remotely and decided to pull out my portable ASUS monitor and had the same issue. The monitor typically powers up in seconds but when plugged in it would power up briefly then no display. I then plugged the monitor into one of the right hand ports and it worked. Please advise

Same problem. I have a Dell U3415W - tried everything HDMI, mini dP, screen flickers every few seconds. Very frustrating - I cannot believe that Apple allows these type of nasty bugs and do nothing about it. Years back, I moved to apple because of software, now, I may leave apple because of software. Apple, if you are reading this forum, please do something about it.

Apple recently released an update for the 16 inch; since then I have had better luck connecting to my external via HDMI. Better being the key, it still has issues when I connect initially but will eventually work. I will plug it in and then remove and replug in the cable and it'll begin to work. This resolution only works if I have my MacBook open and awake/powered on first. It does wake up using my external keyboard or mouse but only after falling asleep while plugged in and used initially. Strange stuff

Upgraded to the latest software, did nothing to resolve this issue. very frustrating. I am going to try couple other HDMI adapters and if they don't work, I might switch computers - If anyone has any ideas, appreciate your help.

MacBook Pro 15-in or 16-in features dual graphics chips. The Internal display can run off Integrated graphics, but when you connect an external display, the Discrete graphics processor is always used. There is not even any wiring that allows the Integrated graphics chip to be used for an external display.

So when you are complaining about the External display, you are also implicating the Discrete graphics processor. A Hardware failure in that graphics chip could produce the symptoms described.

When you invoke Mirror Displays, they are physically connected. The Mac always uses EXACTLY the same display buffer and rasterizer circuitry for both displays. So if you mirror a flickering display to the built-in display, the problem may become a problem for the Internal display as well. (When mirroring, a different compromise resolution that both displays claim to support may be used.)

Ok, thanks for the info. What about the wake from sleep issue and the external display (external display does not wake, MBP either wakes or does not)? Not sure it is part of this thread but has been mentioned in numerous other threads. Problems seem to be related to each other and widespread. You seem to know your stuff.

Experiment: Use Mirror displays to connect both the flickering display and the internal display together.

If the flickering follows onto the Internal display, you likely have a Hardware problem in the MacBook Pro.

If the external still flickers when mirrored, but the internal is fine, it may be a ThunderBolt port problem or a cabling problem.

If using HDMI, I am immediately suspicious of the cables and adapters. HDMI was invented for HD TV sets, and it is being stretched really far to do higher resolution displays. Often the cables are inadequate. Making it work seems to involve some black magic.

rtgtrovador--

Although there is a little bit of circuitry in the Mac that COULD be problematic, if you are doing the suggested Mirror display experiment and the issue follows the external display and does NOT appear on the Internal display (using the same graphics generator in the display chip) you have almost certainly isolated the problem to cables and adapters or the display itself.