M1 Won't Wake External Monitor

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 (from another display, such as the built-in)

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.

Try waking with your mouse instead of your keyboard. I could not wake my M1 MacBook Air in clamshell mode attached to an external monitor with the keyboard as reported by others. Works flawlessly with the mouse. Press some buttons on your mouse and/or wiggle it a little. Works every time for me. HDMI connection.

I have this problem too. I use MBP M1 connect with external monitor Samsung S23C350 with Orico hub. But I noted that both monitor will dim down until black after 1 min (Battery Preference set up) an I can wake them both if the percentage of battery more than ~20%. If lower external monitor will won't wake. You have to plug the charger before wake them and you 've never face this problem whenever you're plugging.

Guys, I think i have a fix.

Disconnect everything from the USB C/HMDI adapter except your mac and hdmi cable to the monitor. No PD power in. No USB devices connected to the adapter. (Also first disconnect everything from the USB C adapter and wait 30 secs for it to completely reset.)

Since doing this, my mac will always wake up the monitor. No more opening the lid, unplugging/replugging (which did not always work anyways).

I still have the issue of waking up to the wrong resolution. But is is much easier to fix now that I can see the screen at least.

My setup is 1440p@60hz and retina. macOS 11.2.2. M1 Macbook. It has worked for over 1 week. I have not dared to change this setup. The second USB C port has a hub with the PD input and other USB devices.

I updated the macOS to 11.3, and my monitor issues have been resolved by this update.

My issue was with both the DP1.4 port on the monitor and with the HDMI port on the monitor. I haven’t tried HDMI after the update to macOS 11.3 because my monitor is 5K @60Hz, and the HDMI port on the monitor maxes out at 4K @60Hz, so there’s no point for me to use the HDMI port as long as the DP1.4 port works properly. But there’s a good chance that macOS 11.3 has fixed the HDMI issues as well.

My problem and its weird resolution -- using CalDigit box with HDMI to CalDigit Display port active adapter. Worked the first day. Wouldn't work the second day (not picking it up on System Preferences - Display). Searched google. Suggested I put MacBook Pro into Sleep mode for 10 seconds (with monitor on). Opened computer back up and display is now working. Say what?? Really.

Biggest concern is this fix won't work every time.

Just get a direct USB-C to HDMI 2.0 cable. Something like this:

USB C to HDMI Cable for Home Office 6.6ft (4K@60Hz), Atvoiti USB Type C to HDMI Cable [Thunderbolt 3 Compatible] for Mac-Book Pro 2020/2019/2018, Pad Pro 2020, Galaxy S20, Surface Book 2 and More https://www.amazon.com/dp/B08P44HZKS/ref=cm_sw_r_cp_api_glt_fabc_0A11PVDDG45DXGDCA0E9?_encoding=UTF8&psc=1

The key for me was upgrading to 11.1 (from 11.0.1).

This addressed all issue of waking up, HDR color and resolution.

I have a no-brand 5K monitor that uses a DisplayPort 1.4 connector to receive 5K signal from the Mac, using a USB3-to-DP1.4 cable (capable of up to 8K at 30Hz or 5K at 60Hz). It works with all Intel-based 2019 and 2020 Macs that use the Titan Ridge TB3 controller and discrete graphics adapters. It also works with the 2020 10th generation Intel CPU Macs (MacBook Pro and MacBook Air).

This display is not detected by the M1 MacBook Air as though it’s not even connected. My 2020 10th generation Intel 13” MacBook Pro detects this display and sends a 5K video signal to it.

This display also has a USB3 input that uses USB3 alternate mode with DP1.2 (4K resolution). Again, the M1 MacBook Air doesn’t even detect the monitor when connected to the monitor’s USB3 port via a Thunderbolt3 cable (TB3 cable). The Intel-based 2020 MacBook Pro can detect the same monitor when connected to its USB3 port via the same TB3 cable and can send 4K signal to it.

The only way I can connect to this display from the M1 MacBook is via this display’s HDMI port, using a USB3-to-HDMI adapter made by HyperDrive and an HDMI cable. This way the M1 MacBook Air can detect the monitor, but the signal is 4K only (of course), and the connection from the M1 MacBook Air to the monitor is flaky. After the M1 MacBook Air goes to sleep and the monitor goes on standby, it takes a while for the monitor to wake up. It’s basically almost unusable.

I tested the M1 MacBook Air with a 27”Apple Cinema Display (non-Thunderbolt version), and that display came up instantaneously when I connected the M1 MacBook Air to it via the same Hyperdrive USB3 adapter (it supports both HDMI and mDP connectors). I haven’t tried the M1 MacBook Air with a 27” Thunderbolt Cinema Display (which I also have), but I suspect it will work just fine with it.

From my tests tonight, it appears that the M1 Macs have an issue with USB3 alternate mode using DP1.2 and DP1.4 in that such external monitors utilizing these modes of connecting to the M1 Macs are not detected at all.

Obviously, the M1 Macs are also having some compatibility issues with HDMI monitors in that the monitors take a long time to wake up.

I filed a trouble ticket with Apple on this issue today, and it was sent to Engineering. I should hear something from them by January 9.

Try to wake up the monitor with your mouse instead of your keyboard. That worked for me. Push the mouse buttons. Jiggle it around a little. Hope it works for you too. I have an LG monitor and an M1 MacBook Air.

Try this trick. If you use an external keyboard, start hitting the space bar on it repeatedly in a quick succession without a stop until the monitor wakes up. It could take 20 times or more.

They told me they knew there was a problem with HDMI connections after telling me there were no issues. I really had to press them to admit. Of course, I didn’t speak directly with engineering, so I had to go via the Senior advisor, who was a total jerk.

My HDMI connection works, but it takes connecting and disconnecting the monitor after the Mac goes to sleep. After I re-connect the monitor, it takes another minute for the Mac to display to the external display with me pounding on the spacebar repeatedly.

However, my goal is for this monitor to be connected via its DP1.4 port so that I can send 5K to the monitor. The M1 MacBook Air doesn’t detect the monitor via the DP1.4 port at all, whereas the 2020 Intel-based (10th generation) MacBook Pro has absolutely no issues displaying 5K to this monitor via the monitor’s DP1.4 connector.

[Edited by Moderator]

I've finally had a breakthrough tonight with my 5K monitor that has a DisplayPort 1.4 (DP1.4) port for receiving 5K @60Hz.

To recap: this is a non-brand Chinese made 5K monitor that has an LG 5K panel (same one that's used in LG Ultra Fine 5K monitors and in 5K iMacs). This monitor has the following ports:

USB3 (DP1.2 only - 4K @60Hz maximum)

DP1.4 (5K @60Hz)

HDMI 1 (4K @60Hz) maximum

HDMI 2 (4K @60Hz) maximum

In the fall of 2020, I purchased an M1 MacBook Air and quickly discovered that the M1 MacBook Air could not even detect that an external monitor was connected when I was using the same TB3 to DP1.4 cable and the same DP1.4 port in the same monitor. So, not only could I not send an image from the M1 MacBook Air to this monitor, but the M1 MacBook Air wouldn't even detect that an external monitor was connected (as it was evident from the macOS System Information utility > Graphics/Display, i.e only the built-in display was detected by the M1 MacBook Air.

So, tonight it occurred to me that there was one adapter (of many, trust me), in my desk drawer that I've never tried. That was a TB3 to dual-DP1.2 adapter, which is meant to either connect two 4K monitors via DP1.2 (one monitor into each port on the adapter), or to connect both ports to a 5K capable display via two DP1.2 ports on the monitor to stitch two signals into one 5K @60Hz image. For that to work, the 5K display must be capable of receiving two DP1.2 signals (each signal via its own DP1.2 port on the monitor) and then internally stitch that image to make it 5K. That's an old technology (before DP1.4 standard was released) that was the only way for a monitor to display 5K without having to use Thunderbolt. With the release of DP1.4 standard, it became possible for a monitor to receive a 5K @60Hz signal via a single DP1.4 port. My Chinese-made no-brand monitor has the ability to receive a 5K @60Hz signal via one DP1.4 port, but it has no ability to stitch a 5K @60Hz signal from two DP1.2 signals. That was the reason I never opened that TB3 to dual-DP1.2 adapter.

So, to my great surprise, when I inserted the TB3 to dual-DP1.2 adapter between the M1-based Mac and my monitor connected one of the adapter's DP1.2 ports to the monitor's DP1.4 port with a DP1.4 to DP1.4 cable, my monitor came on instantaneously, and not only did it come on (for the first time) via its DP connector when connected to the M1-based Mac, but the signal was 5K @60Hz. Now, the most I could hope for the signal to be 4K @60Hz because both ports on the TB3 to dual-DP1.2 adapter are both DP1.2 ports, which are not capable of more than 4K @60Hz. But, strangely enough, the signal received by the no-brand Chinese-made monitor via its DP1.4 port was a genuine 5K @60Hz. Trust me, by now I know how to tell for sure. I've verified that the signal was in fact 5K @60Hz (both in the monitor menu utility and via the macOS System Information.

Now, I thought maybe the TB3 to the dual-DP1.2 adapter was mislabeled, and perhaps the ports on this adapter are not DP1.2 ports but DP1.4 ports. That would explain how my monitor is able to receive the 5K @60Hz signal from the M1-based MacBook Pro via this adapter. So, I pulled out my 13" 2020 MacBook Pro (Intel-based 10th generation CPU) and connected it to the same monitor via the same TB3 to dual-DP1.2 adapter, and guess what I found out? You will not believe it. The 13" 2020 MacBook Pro (Intel-based 10th generation CPU) was sending a 4K @60Hz to the monitor, just as I would have expected it to because the TB3 to dual-DP1.2 port adapter is not supposed to be able to send a 5K @60Hz toward the monitor out of a single one of its two DP1.2 ports (because the DP1.2 specification maxes out at 4K @60Hz).

So, I don't know exactly why this adapter solved my issue with the DP1.4-based 5K monitor, but it works perfectly. Moreover, the monitor wakes up as soon as I press a key on the external keyboard. There's no unpluggin/pluggin back and dancing with a tambourine around it for 5 minutes required. It works absolutely perfectly with the M1-based MacBook Air. The magic is in this TB3 to dual-DP1.2 adapter. My suspicion (and it's my suspicion only) is that Apple wired something wrong from the GPU in the M1-based Mac to the USB4 port. I actually suspect this is a hardware issue and not a software issue. Somehow, this TB3 to dual-DP1.2 adapter not only mitigate this incorrect wiring in the USB4 connector on the M1-based Mac but it also allows for the 5K @60Hz signal to be passed to the external DP1.4 based monitor out of the adapter's single DP1.2 port (which is not supposed to happen, and which is not happening with the Intel-based Macbook Pro).

For the rest of us, here's the information about the adapter that fixed the issue of DP1.4-based monitors not working with M1-based Macs:

Vendor: OWC (Other World Computing; aka MacSales.com)

Part Number: OWCTB3ADP2DP

Name: OWC Display Adapter Dual DisplayPort with Thunderbolt 3

My M1 Mac Mini since upgrading to 11.1 and using a new LG 5K ultra wide 5120x1440 and the USB-C port, it works 100% of the time.

I did speak with LG before I went to 11.1 and they said a new driver was needed... I think that came in 11.1.

Yes, of course. You should open a case with Apple on this.

Update on my case: after a month of the car being open, Apple sent me with my monitor to the local Apple Store, which confirmed that the monitor worked with Intel Macs but doesn’t work with M1 Macs via the monitor’s DP port. The Apple Store documented it, and ... I haven’t heard back from Apple since then. Am I surprised? In the past 13 years of using Macs, I’ve had at least a dozen issues being sent to Apple Engineering, and NONE of them got resolved.