MacBook Pro 16 external display issues

For additional testing, you could enable [√] Mirror displays. This runs BOTH displays (using a compromise resolution) off the SAME display hardware, except for the last output, which you have already debugged by trying multiple output ports.

If the internal display does not go off, but the external display does go off, that vindicates the internal graphics hardware, and suggests the problem is occurring in the final output or the adapter.

If you have run exactly this experiment, Readers would love to hear your results.

sticzed wrote:

...

I’ve solved the problem by buying new adapter. The one that works well in this case is club cac-1510.

...

That is good information.

But you never posted any other information on this thread, so we still don't know about other folks (especially the Original Poster) results for these experiments.

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

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.

Okay after doing the Reset NVRAM or PRAM on your Mac – Apple Support I have been using the USB-C hub with the HDMI cable plugged in to the adaptor and everything seems to be okay now after 2 days.

So fingers crossed.

This page shows that Eizo issued a compatibility update statement for MacOS Catalina on Jan 10, 2019. Did you take a look at that?

https://www.eizoglobal.com/support/db/products/model/CE240W

.

Just an update, and wondering if anyone else has noticed the same.

I have had my external monitor attached using the adaptor via the right side USB-C sockets and I have not had the same issue as I have had when it was attached to the left side.

I have the same deal. Brand new MPB 16 and a LG external monitor. Went and got a better HDMI adaptor/cable with beaucoup shielding because the first one kept losing signal due to RF interference (and also wonking out the mouse - it'd skip to the point of being unusable). It was so on-edge that sometimes me just standing up would be enough to drop the external monitor. Better shielding fixed that.

Anyway, every third or fourth time I wake it, it can't find the external monitor and the main monitor is black, but flips on for 1/2 a second every 3 or 4 seconds as it tries to find the external screen. Everything thinks it's running properly - the touchbar lights up according to what apps are running - you just can't see a **** thing. It never leaves this state until I unplug the HDMI. Then the main monitor is detected and things start running properly. But ...

The settings are trashed. It's reverted to default settings. Sometimes the Night Shift settings vanish in the case. Sometimes the Color Profile is screwed up and has to be re-selected (even though the proper setting is in the panel). Sometimes the TrueTone settings are hosed and you have to sleep/wake again to get it back.

Even when it wakes properly, half the time the external monitor didn't wake before WindowServer resumed, so all windows I had on the external are now on the internal. So I gotta move things back to where they were. I got DisplayMaid to help with this, but since I use workspaces, that means I have to shuffle through each one still and restore each window set. It's a royal pain - and I never had this problem on any other MBP (this is my fourth one in the last 12 years) - I'm pretty disappointed in the sudden loss of dependability as that's a big reason I pay extra for Apple products.

I don't think it's a problem in the video circuitry as this only seems to affect monitors hooked up via USB, and once everything wakes up it's rock solid all day. It's something in either the firmware or OS that handles detecting external monitors and initializing things before WindowServer starts working. If it is hardware-related, it's probably in the USB-to-video circuitry not detecting a connected monitor properly and entering some weird loop state.

Please fix this mess.

Since taking the 10.15.4 (19E266) update, I haven't had the external monitor wake-up problem happen once.

That movie shows your display going dark for about 8 seconds at a time. That is no ordinary problem.

For additional testing, you could enable [√] Mirror displays. This runs BOTH displays (using a compromise resolution) off the SAME display hardware, except for the last output, which you have already debugged by trying multiple output ports. If the internal display does not go off, but the external display does go off, that vindicates the internal graphics hardware.

My guess is that you have an interface problem, and should replace your adapter with a new one. The new MacBook Pro may be sending data far faster than the old computer ever could, and the adapter may be losing Sync.

I have the same problem. One thing I tried that helped was to set the primary display as the display on the MacBook Pro rather than the external display. This has greatly reduced the frequency of the wake from sleep issue for me.

WhiteCubes wrote:

Thank you, but no :-) One port per display (same configuration that worked for years with Macbook Pro Retina 15").

By the way I was forgetting, some days (like today) I just find the mac restarted due to "Panic: Sleep transition timed out after 180 seconds while entering darkwake on way to sleep." (obviously I send the report)

System Preferences > Energy Saver ...

turn OFF 'power nap' and similar features.

Hello mamrotek,

Thanks for reaching out in Apple Support Communities! I understand you're having trouble with your external display. I'm happy to assist you with this.

Check out this article for troubleshooting steps to help resolve this issue:

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

Thanks for using the Apple Support Communities, and have a great day!

That certainly sounds like a mess. Unfortunately, readers here are other Users, and your problem is serious enough you should contact support. You can call the AppleCare 800-number of use the "contact support" link at the top of every forum page on a computer-based Web browser.

Same here. When I called in the tech tried to be helpful, but seemed unaware that many people were reporting issues online. Or maybe he was told to deny knowledge. Who knows?

FWIW, one thing I've found that's helped is that the problem seems less severe if I plug the HDMI into the port on the left side, where you'd normally put power in. Maybe it's because there's less RF interference since I have my external monitor on the right, or maybe the circuitry is different. Again: who knows?

Once things start acting up, I have to reboot within a day or so. Otherwise sure enough I'll open the lid and the machine will be black-screened and need a hard reboot.

I'm beginning to suspect this is a combination issue. Part is the OS not discovering monitors in a reliable way. And the other is the USB-C stuff has some glitch when it comes to pushing video through it. In hindsight, I should have waited six months to avoid these teething problems with a new Apple product.

(And I won't even get into how the font-smoothing is screwed up on many external monitors ... how can you release a high end product and have this?)