Monterey 12.3.1 External Monitor/Display Issue - No Longer Outputting Signal

Same issue here.

Macmini i5 2018 + LG 4K display

After updating my display went black after logging. It back to work when I plugged it on HDMI port WHILE USB C is connected.

After I connected the display on two ports and I got it alive, I changed its resolution to standard res (4K zoomed to looks like 1080p) or pure 4K and it works!

On any scaled res it goes black.

But my fix is not fully functional. When my computer goes to sleep, my display doesn’t wake up.

Please guys, open the Feedback Assistant and report the bug to Apple

When I upgraded to 12.3, I lost the ability to use two external monitors (Adding a second external display to my M1… - Apple Community). Apparently, the specs for my M1-iMac have never supported it, but it woked anyway until Universal Control was implemented. I had to spend $128.07 for a display adaptor and install DisplayLink. Apple's genius folk had solutions that didn't work.

Fixed: After trying all the advertised solutions for months I finally found a fix that has worked flawlessly for three days now.

I have a MacBook Pro (Monterey) and WAS using a "HyperDrive SOLO Hub for USB-C Devices" docking station to connect my hp external monitor via HDMI. The monitor would work for a few minutes, then start flickering and go off and on. The docking station was the issue (not a great design).

The fix was changing the Hyperdrive to the "Upgrow USB C to HDMI Adapter 4K@60Hz Cable Type C to HDMI Adapter [Thunderbolt 3 Compatible]" purchased on Amazon for . ZERO issues for three days.

I hope this helps someone with similar issues.

I was using 2 external monitors just fine until MacOS 12.3 (with universal control) came out. After a lot of work (including reinstalling Monterey), they told me that my M1 iMac can't handle 2 external displays. They sold me two HDMI adaptors, but only one display would work at a time. I returned 1 and wish I had returned both $70 displays as my solution didn't use it.

My solution was to buy https://eshop.macsales.com/item/OWC/CADPDL2HDMI/

OWC USB-C DUAL HDMI 4K DISPLAY ADAPTER WITH DISPLAYLINK and install DisplayLink.

What cables/adapters are you using to connect you monitors?

Did you already ask them to send you the official USB-C AV multiport adapter to try (for free, of course)? It's an HDMI->USB-C adapter and no idea why but my second monitor works with that one, even though it requires converter cables to connect both of my monitors if I'm using it, so it's only a temporary fix for me while I'm still waiting for them to fix this, so I can finally use my regular adapter with just regular cables again.

Hi,

I was able to get it to work with my old monitor. I got the clue from this email thread. Instead of connecting the HDMI cable from the external Display into HDMI interface of my Dongle (it is multi-purpose - SD Card reader, USB Port, Network Port, Power), I got a new HDMI - USB-C cable from Amazon. I connected it directly from External Dell HDMI display to one of the USB Ports of MAC. Again this is a new HDMI -> USB-C cable, not the old HDMI -> HDMI cable. The Mac OS is Monterey 12.4. So it is now working in Extended Display mode. Hope someone will find help with this information. B083Z8QBJ5

It worked.

Dont know why, but 5k 72Hz is back again.

MB off, Monitor off and unplugged. Used the Apple TB cable to connect them, plugged in monitor.

Starting the monitor which also started the Mac.

All fine. Lets see if it stays stable.

Having the same issue here, using SwitchResX (trail version) to force resolution worked fine.

Setting it back to 1.4 on my BenQ 3220U fixed the problem.

Nothing has worked for me so I had to take it back to BigSur - and it works FINE….very frustrating

try unplugging you monitor's power source. then plug it in. it should be fine now

Still not working after upgrading to Ventura.

What an absolutely ridiculous bug.

Edit: Changing the monitor's color profile kind of fixed the issue. I stand corrected: what an absolute idiot I am.

I just wanted to add, I am using a 13" MacBook Pro, 2019. I use a usb-c to usb-c portable monitor 15.6 by Lepow. It has worked perfectly since 2020 until the 12.3 update. I have done countless restarts, unplug, plug in, reset NVRAM PRAM also multiple times, I tried HDMI on a USB hub I have and finally I tried setting up a new account since that seems to have worked for some people. Last week, after multiple calls to support, they had me plug in and unplug the monitor and then record the logs and send them in. I received this reply: "...I just got a response back from engineering and they said that the logs came out perfectly (whew!). They also confirmed that this is apparently a bug (so we were both right in that respect). He added that they are supposed to be coming out with an update soon that will fix the problem, which is a relief. I can’t necessarily say WHEN the update will be out, but the language the engineer was using led me to believe it should be soon...."

I am really struggling without the use of a second display. I even ordered a new one out of the box JUST IN CASE it would work. It did not so I returned it. My portable display works fine on my mid 2012 MacBook Pro running Catalina 10.15.7 but I cannot use that as a main computer for work.

If anyone has any other suggestions on what I can try to do to get my display working I would appreciate it.

Hi,

I tried a lot of things.

Then, I saw this suggestion on MacRumors : USB problem just inverse polarity of connector.

I have an old Dell plugged in HDMI into a USB-C Digital AV Multiport Adapter from Apple.

I disconnected the adapter, inverse the direction USB-C in the Mac and plugged it back in my iMac 2017 5K.

The monitor was instantly recognize and is working fine so far.

I think I may have figured it out. After a lot of trial and error, switching monitor signals and everything I could try (I spent over 2 hours trying to come up with a resolution)

I would try the following

-Plug the display port from the mac into another computer and switch it to another display port setting. (I went to 1.1)

-changed cords to make sure it didn't work with the other cord.

-I reset the computer 3 times and turned the monitor off and unplugged it.

-Once I did that I turned the computer on a 4th time and I plugged it in and it started to work again.

Hopefully this helps. It seems like I just had to cycle through it.