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

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.

Hello GolpherZX,

Thanks for reaching out to the Apple Support Communities! I understand that you are having an issue with your external displays. I'm happy to help you find some information.

Here is a resource that can assist you:

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

If you have an issue after reviewing the links, please contact Apple support.

Have a great day!

Worse for me after the 10.15.3 update. Now when I wake the monitor is off in Tint display and appears pinkish. Have to unplug and reconnect manually VGA cable, since HDMI causes flicker issues. In one of those several instances the whole thing just crashed. Did that thing where fans spin and whole things just shuts off to restart. Not fun!

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.

@rtgtrovador

Did you every find a fix for this? I'm having the identical issue. I'm using the same Dell WD15 hub. Worked fine with my 15" MBP, now the External monitor flickers with the 16". I guess it's hold my breath for a patch or upgrade to a different hub, at which point I'll probably start looking at another monitor solution.

@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 a similar issue with an external display (LG UltraFine 5K Display) where sometimes the MacBook Pro doesn't recognize that it has the display connected to it. This is usually when it wakes from an extended sleep. I have to restart the MacBook Pro, disconnecting and reconnecting the cable doesn't seem to help. It is connected via the Thunderbolt 3 cable that came with the display (uses one cable to charge and feed video). I have the display set as my primary display with menu and the MacBook Pro is the secondary display. Prior to this display I had the original Apple Thunderbolt Display that I connected with an adapter. Same thing was happening, so I thought it was the display and adapter, which is why I purchased the new display. Anyone else have this issue or a solution?

Update: I'm not a pro but I was able to get my hands on several different (all Dell) hubs from my wife's work. All had the same issue. I know it seems like a port/driver issue but it seems that a lot of people are having similar problems with these hubs that don't push enough wattage (That Dell pushes like 65w I think). This doesn't explain it for folks with LG Ultrafines. I hooked up my Dell with a temporary solution/ and Anker 7 in 1 USB-C adapter. I'm in business. Now I'm considering upgrading to one of these Dells that they just announced at CES. Run 90w USB-C geared towards running/charging new MacBook Pros.

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?

I started with the LG-supplied Thunderbolt 3 cable and switched to the Apple Thunderbolt 3 cable. The not-waking-from-sleep issue is happening regardless of which cable is being used. And it happens whether the LG monitor is supplying power or the Apple Power Supply. Many threads about the wake-from-sleep issue, so thinking it is not a cable issue. Hopefully fixed with a software or firmware update from Apple.

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences --especially on a MacBook Pro

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.