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

Same-ish. Was using a USB-C dock (Dell WD 15) that connected a Dell Display via HDMI on the 15", plugged in the 16" and the display flickers, green/static and now even the Ethernet isn't connecting. Tried display with portable dongle, works fine! It also charges sporadically, thought maybe the Dock wasn't pushing enough power for the hungrier MacBook Pro 16", used a 185w power brick to the Dell WD 15, which it supports, made no difference. Would hate to reconfigure my one cable setup, hoping update would patch it up, no such luck, problem persists with Catalina 10.15.2 I can continue using VGA as that seems to work, not HDMI, but the rest of the dock is partially functional, no Ethernet, power, USB unreliable.

The Apple power supply is 94 or 96 watts, the LG 27" is only 85 watts. I've noticed under heavy load, where the fans spin up, that the battery drops below 100%. I am now using the Apple supplied power supply and the monitor is just supplying video via the thunderbolt 3 cable.

Inadequate cables and adapters are a common cause of display troubles. Many have no hope of running at the high resolutions demanded by today's displays and provided by today's computers.

Exactly what cables, hubs and/or adapters are being used, and what protocol conversions are they performing?

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.

If your aock uses DisplayLlink chips and software internally (includes most docks that require a Driver), to produce a "legacy" display Interface (other than DisplayPort) its Driver can not load under 10.15 Catalina, and you may need to get a new driver from the manufacturer or DisplayLink.com

I have this same issue. I just got my 16" 2019 MacBook Pro 3 days ago. Previously I had a 15" 2016 model. I migrated from the 2016 to the 2019 via Migration Assistant so the software setup is fairly identical. I never had this issue with the 2016. Everything is the same (software, hub, monitor, cables). The only thing that has changed in my setup is the physical laptop hardware.

I have a USB-C Hub with a monitor attached via HDMI. When I leave the 2019 MacBook overnight (and it goes into sleep mode), attempting to wake the machine results in a flickering loop where it's trying to initialize the displays over and over. If I unplug the USB-C hub (and thereby the external Monitor and everything else) the MacBook wakes fine. However, once I plug the hub back in I start getting the flickering loop again. Rebooting is the only thing that lets me use the hub/external monitor again. Again, this never happened with the 2016 on an identical setup. There is clearly an issue with the 16" 2019 MacBook Pro. My hope right now is that it's not a hardware issue and they can fix it through software. Other than this issue I love the machine so far.

For what it's worth I have a LetsCom USBC002 hub and the monitor is a Philips PHL 276E9Q. My MacBook has the AMD Radeon Pro 5500M 8GB graphics hardware.

The web page on the display says it is capable of 1920 by 1080 at 75 Hz. Is that what it is running?

That is a little faster than most docks are ready to supply, so there could be a mismatch between what your new Mac is sending and what the old Mac could send. is that the same refresh rate it was running on the old computer?

Readers here are all other users like you. Apple does not troll the forums looking for complaints -- it only works on fixing problems that have been formalized into a Bug Report with enough additional information provided to attempt to reproduce the issue in their labs.

I am trying to think of things for you to consider to get to the bottom of this.

If you do not want to do any more debugging yourself, please take the opportunity to contact Apple Support to get your complaint on record. Make certain the person you are dealing with knows that your problem is NOT solved, if that is the case, and do not let them dismiss you without filing a Bug Report. Start with the "Contact Support" link at the top right of every forum page..

Sometimes Apple breaks things by enforcing standards that should have been there all along. That is not what they should be doing, they should give you an error message instead.

I suggest you make certain your cables and adapters are all certified to run at the high speeds involved, and consider upgrading them.

system Preferences > displays ...

... hold the Option key and that button appears in the lower right.

do you have the latest DisplayLink driver for your Dock, if it uses a Driver?

Hey, I have this issue all the time with macbooks. Have you tried going into Energy Saver in preferences and disable the automatic graphics switching?

@Planet51 No fix as of yet. I can use with VGA, or as I have actually been doing, using a J5 Create hub (JCD383). Just plugged in to try and nothing. With the Dell WD15 the Ethernet port would work as well with the MBP15, doesn't with the MBP16. Bit of a pain, but on same boat with starting to look for other hardware solutions as well soon.

Having the same issue. At first I thought it was the Hyperdrive USB-C hub I was using. Tried two different Hyperdrive models and had the same problem:

When I first turn on the MacBook Pro 16" it wakes up the external monitor as well (Asus PA248) which is connected via HDMI cable. But often after the computer goes to sleep, and I wake it up, the external monitor and MacBook monitors start flashing on and off until I unplug the external. So I ordered a USB-C to DisplayPort cable, and I'm having the exact same issue. Monitor always worked fine on my Lenovo PC and previous 2015 MacBook Pro 15" before now. So I'm assuming it's the MacBook that is having the issue.

If I restart the MacBook, the problem ceases. But I don't want to restart my Mac every time I step away for a few hours, or leave the Mac running 24/7.

For whatever it’s worth. This issue just “went away” for me after a few days. I think I did a VMWare Fusion upgrade during that time but that’s the only change I can think of. Maybe it was that or maybe it was coincidence. Worth a shot if you’re running VMware.