Anyone experiencing no signal output to the external monitor using USB-C after 12.3 upgrade

[Chancha]

On my iMac 2017, 12.3.1 did fix my bus-powered type-C 15" FHD display.

 

[FunkyMonkTan]

I have an M1 MBA. I have a Samsung M7 monitor connected via USB-C. All was working well until I updated to 12.3.1. Under the Settings -> Display, the Samsung monitor is detected. However, the monitor is not receiving any signal. I factory reset the monitor, changed cables, rebooted my MBA, still nothing works. I hope will release a fix very soon.

 

[FunkyMonkTan]

Update: Problem solved. I unplugged my monitor from the power outlet and plugged it back in. It is working now.

 

[PeteBurgh]

Yes, I also have this issue with a 2018 Mac mini - annoying!

Hopefully there is a x.x.1 fix coming...

For the record, 12.3.1 update did indeed fix it for me. Phew. That was an annoying but mercifully short-lived bug.

 

[nik1aa5]

Same on my M1 Max 16". LG32" 4k via usb-c. Changed display port from 1.4 to 1.2. No luck. Then as recommended above, simply unplugged the LG from power then plugged it back in and now it works

Thanks for that hint! I just got it working with version 1.4 again: I unplugged the display from the notebook, switched from 1.2 to 1.4, unplugged the monitor from power, waited 20 seconds, plugged the monitor into power, and then connect it to the notebook.

 

[Spanther]

Thanks for that hint! I just got it working with version 1.4 again: I unplugged the display from the notebook, switched from 1.2 to 1.4, unplugged the monitor from power, waited 20 seconds, plugged the monitor into power, and then connect it to the notebook.

I did this too, seems to have done the trick!

 

[varap]

I usually do not comment on forums, but let me try to offer some help!!
After updating Catalina 10.15.4 to Monterey 12.3.1 in a 2019 MBP 16"(intel), I bumped into a similar problem. After restarting the Mac several times, disconnecting the reconnecting the wires and trying almost all the tricks I could find on the internet, they didn't work. Finally, I decided to tinker with display preferences by lowering the Refresh rate to 47.95 Hertz and changing the colour profile to "Colour LCD," then after 20 to 30 seconds, voila it worked. Returning to refresh rate back to 60 Hertz will render your display useless again. Hope this will be helpful for those who bumped into similar challenges. For those whose colour profile and refresh rate are crucial to their workflow, the display I'm using, DELL E2214H, 21.5 inches (1920 X 1080) shows Colour Profile: Display P3 and Refresh Rate: 60 Hertz which was there by default, which is decent right?. Hope this will work for you too as we eagerly wait for the update to fix the mess.
Sounds fishy, there are no external display issues reported for those using Studio Display

 

[willyin93]

Mine is a Samsung 28" 4k monitor.

Is it the Samsung Odyssey g70a 28"? I just bought one recently. I have been trying to use this as a dual monitor with my MBP 2019 16" that's running Monterey 12.4, but no matter what I do I can't figure out the settings. Any potential solutions?

 

[nigh7sh4de]

Was really struggling with this issue with 2x Gigabyte M27Q's connected to my 2021 Macbook Pro 16. I had to buy thunderbolt 3 cables (i got a pair of 10' 20gbps cables), and that worked for my personal laptop (Lenovo Yoga 13, maybe 2018 or something?) but my work laptop (the macbook) would only work with one monitor at a time. Tried turning the undetected monitor off/on, replugging, nothing helped.

What worked for me was going to my monitor settings and disabling "Auto Switch Inputs", and then switching to USB-C as my input source. After about 15-30s with a couple flashes the monitor turned on and suddenly my macbook recognized that it had 2 displays connected!!!

 

[CreatorX64]

Just had the exact same issue on macOS Ventura 13.4.1 with my LG monitor (4K 27UP550-W).

TLDR; I unplugged the power adapter of the monitor, left it unplugged for ~2-3 mins, then plugged it back in. This resolved the connection issue.

Some context: I have been using my monitor via HDMI => USB-C dongle since I bought it because I didn't have a USB-C connection cable until last week. After I got my hands on a USB-C connection cable I ditched the USB-C dongle and made a direct USB-C connection. Everything worked fine for the last week until this morning when I booted up my Mac and the monitor didn't connect, displaying a "No Signal" message. I researched a little bit and found out that someone in this thread left their monitor unplugged for the night and it resolved the issue for them. So I tried the same thing but left my monitor unplugged for 2-3 mins instead of a whole night, which resolved my issue as well. It's weird as hell....

 

[champwolverine]

Same issue here. I have M2 macbook pro with Ventura 13.5 and the monitor I have is 4K LG 38” monitor.

Someone please help me. I have tried everything I saw online. My usb c to monitor directly was working fine until yesterday, I unplugged the usb from monitor to move the cable and after plugging in, I get no display. I have reseted the monitor, I restarted the mac without connecting usb c. I even reseted NVRAM from recovery mode. I plugged off the power from monitor. I bought new usb c cable but no luck.

What works, Usb c to dongle with HDMI works, If I connect usb-c to monitor usb-c then it charges but no display.


All I got left to do is cry. I have been spoiled with USB-C and using hdmi sucks.