M1 Macbook air external display issues with usb-c

Hey sparrowhawk360,

Initially, I just ran the monitor firmware update (PA279CVFWUpdateToolV019) and everything worked fine. Since I had the Hub firmware update (PA279CVHubPDFWupdateforMacOS) handy I ran it as well so that it's all up to date. When I ran the Hub firmware it didn't recognize the USB C connection. After a brief freak-out, reboot, trying to re-run the monitor firmware update (which didn't work because it was already updated) and few on/off it resolved itself and is now working fine.

Note that the most recent firmware update is v019: https://www.asus.com/us/Displays-Desktops/Monitors/ProArt/ProArt-Display-PA279CV/HelpDesk_Download/

Exactly the same situation with you, and probably I could help you.

I just bought a brand new m1 MacBook Air and Asus PA279CV. At first, I found the same issue with you in which when I plugged in the usb-c cable to the MacBook, the monitor showed nothing, but it could charge my MacBook. Then I found that, if you shut down your MacBook, then plug in the usb-C cable, then open you MacBook, and you will find the monitor works properly (showing the visual and charging your MacBook at the same time). I don't know why it has to close the MacBook first before plugging in the cable (it is quite not convenient when you are working and want to plug in the cable to continue your job at external monitor), but it is the solution that I can find at this moment.

Hope it helps.

I just picked up an ASUS PA279CV display and had similar issues connecting it to my 2020 McBook Air (Intel) - it did not connect to USB-C but did to HDMI.

I found an ASUS support page with instructions on updating firmware for the USB C problem (https://www.asus.com/us/support/FAQ/1045839/) with a download that includes PDF instruction to update the firmware to v018 via USB flash drive. After updating the firmware it is charging and seems to be working fine.

By the way, if you want the display to run at 60Hz, keep the USB spec set to 2.0 (System Settings > USB Setup). Changing it to USB 3.1 makes the display run at 30Hz)

I hope this helps.

Also make sure you've got a thunderbolt 3 cable to connect an external display, the cable that comes with your M1 MBP is only suited for power ...https://www.apple.com/nl/shop/product/MQ4H2ZM/A/thunderbolt-3-kabel-van-08-m-usb%E2%80%91c?fnode=8c466c39f441688ce5f7a32daea40bf83b96dd42f00da8542fa7ffbb9aa0c5a0f15e3141893d65178b91e2067e2599f95c0f0b1c466b5c67570c14d6690b5404ea91a90a364da3c3b40c90b687a9b674654d7b0882a880c7d615b36c2a419bf30e785efce8d4c2ae244d7d23583ae314

I just picked up an ASUS PA279CV display and had similar issues connecting it to my 2020 McBook Air Intel (it did not connect to USB-C but did to HDMI). I did two things.

First, the USB spec was set at 2.0 so I changed it in System Settings > USB Setup to USB 3.1

Second, I found an ASUS support page with instructions on updating firmware for the USB C problem (https://www.asus.com/us/support/FAQ/1045839/) with a download that includes PDF instruction to firmware version V018 via USB flash drive. This article has additional instructions for M1 but, since my Air isn't an M1, I didn't complete that part. After updating the firmware it is charging and seems to be working fine.

I hope this helps.

Cheers Steve

I had my ASUS replaced yesterday after my first one failed and noted it came with FW V019. So I just ran the Hub Update script and all is working now.

Also using SwitchResX and finally have much faster mouse at 60hz.

I had a similar problem with a USBc-HDMI adapter attached to a TV display and my Macbook Air (M1, 2020, OS X Big Sur 11.6). As usual, the Apple support tech told me to update my OS X, which took an hour and did nothing! While waiting for the update to finish, I found the solution in https://www.lifewire.com/fix-external-display-not-detected-on-mac-5096070. In my case, it was the Retina Display True Tone setting that was clicked on. As soon as I turned that off, it allowed the OS to recognize the external display. That is a bug that Apple should know about and fix! It looks like a lot of M1 users have those knind of problems.

Hi Alfredmm1,

Thanks for reaching out here in the Apple Support Communities. Congratulations on your new Mac!

We know it's important for your external monitor to work reliably and we're glad to help.

Check out this article for more information about the alert you're getting:

If a Mac accessory needs more power or is using too much power - Apple Support

Since this worked fine at the Genius Bar, isolate what might be happening in your setup by checking power sources, cables, and peripheral components, to try to see what's causing the issue.

Take Care.

No signal at all here with a M1 Macbook Pro and a BenQ EW3270-T type EW3270U.

I tried shutdown, plug the monitor, power on but no success, tried with apple and BenQ original usb-c cables.

I reached BenQ and they told me it's an Apple issue. (I think they are right, the monitor is working A1 with my 2018 MBP and my HP laptop.

I reached Apple, at first I was told I have to pay for the thunderbolt3 2M cable at 130$cad (!!!!) Then they told me Apple knows about that issue and engineers at Apple are working on it but there is no time estimate for the resolution or any documented link available to consumers.... That is so lovely when you get such a nice machine with only 2 usb-c/tb3 ports... Somebody didn't complete their homework before putting that product on the market but still ask the big price for a supposedly pro model....

Thunderbolt cable supplied with LG 32UL950-W does not solve the crash after sleep issue, i.e. connection between M1 laptop and monitor when both have been put to sleep. Connection can be reestablished without crashing the laptop by turning off the monitor (rather than sleeping) after the laptop has been put to sleep. After waking M1 laptop, unplugging and then re-plugging the thunderbolt cable back into the laptop and then turning monitor back on yields a working connection. Occasionally establishes a connection without unplugging and replugging. Less than ideal work around, but when the two are communicating, thunderbolt works perfectly, including charging from the monitor.

I have the same problem with a BENQ PD2700u and my M1 MacBook Pro. I am using a Belkin Thunderbolt 3 Dock Pro which is connect to the monitor via display port and to the MacBook via USB-C / Thunderbolt. I tried the trick with the disconnect/close-the-macbook/connect/open-the-macbook and found the MacBook either to crash and reboot or to actually work (50:50 ratio that the MacBook then crashes after a few minutes). Very frustrated with being confronted with this kind of basic incompatibility. If this remains an issue I'll send back the Macbook as I cannot allow my IT-Setup to challenge my workflow so intensively.

What struggles me is that the same setup works perfectly fine with my older, non-4k monitor, a Dell P2421.

I'm having the exact issue here and I'm using ASUS PA279CV as well.

But my device is a MacBook Pro 16", it seems INTEL MacBook could also have this issue?

I also got the message "Unplug the accessory using too much power to re-enable USB devices".

I've done some tests:

• Plug-in the 90 watts power adapter , my MacBook Pro 16" works just fine.
• Unplug the 90 watts power adapter, keep USB-C connected, my MacBook Pro 16" will also works properly until disconnect the USB-C cable .
• As hotinyip suggested, shut down, plugin USB-C cable, open the lid, works fine.

I'm totally confused.

UPDATE: I've had my M1 for a month now and here's what I've learned.

I have an external 24" Dell HDMI monitor. The M1 wasn't recognizing it at first.

I learned that the M1 will recognize the monitor after it's been asleep. At first I thought it had to be asleep for several hours because when it first started working, it was when I'd wake it up in the morning after it was asleep all night.

If the monitor didn't work, I'd put the M1 to sleep for a few seconds, wake it up and the monitor would work. Sometimes I'd have to do this a few times to get it to work.

I had my monitor connected via an Apple dongle and I also had a non-Apple dongle which connected my external HDD and my wired keyboard. For whatever reason, the M1 didn't like having both dongles, so I paired it down to one dongle. That began working better, but it's still not perfect.

My monitor works most of the time but sometimes I still have to mess with it in order to get it working.

None of us should have to go through this much hastle to get something this simple to work. Especially with how much we pay for the M1. It's beyond me why Apple hasn't addressed it yet.

Hope that helps someone out there.