Black screen while working and external monitors are fine

[Timo002]

TL;DR;
I'm using a MacBook Pro 14" M1 Pro and I have 2 external Dell U2520D connected via USB-C. I also power my MacBook Pro from the same USB-C. Every once in a while when I plug in my MacBook I end up with three black screens.

Long story:
When I connect my MacBook with the two USB-C cables from the monitors and open the lid, the external monitors show my desktop and my MacBook also shows a desktop. It notices my Apple Watch and automatically unlocks my MacBook. Then after a second or two, all the screens go black and stay black. Spacebar, Esc, mouse movement, nothing turns on the screens. As if the brightness is 0.

Disconnecting both screens doesn't turn on my MacBook screen, it stays black but unlocked and while I can't see anything, it's just like I'm using it. I can open applications etc., I know this because of some sounds.

When I connect one external monitor, it turns on and shows my desktop on that monitor. Connecting a second monitor does the same. So I end up with two working displays, but my MacBook screen remains black.

When I go into the monitor settings, I see all three monitors. I can change the brightness of the built-in MacBook display, but it makes no difference. I can't get it to light up again.
I have also noticed that the external displays are not scaling correctly. The hover effects of my mouse are on a different part of the screen than where my mouse actually is. However, the click events are fired from where the mouse is on the screen.

Rebooting fixes the problem and I can disconnect and reconnect several times before the problem occurs again.

Does anyone know what could be causing this?

 

[carrlane]

My external monitor for MacBook Pro would display for 10 seconds then go black and display "no signal". In the end I just had to have the computer plugged into external power and everything now works fine

 

[Don MC]

Same problem here. I have a 14” MBP M1Pro and one external display connected via a CalDigit TS3+ dock. Sometimes after I boot in the morning, the internal display stays black while the external one works fine.
I have to shut the computer down by pressing and holding the power button. After a restart, it usually works again.

I hope the latest macOS update (13.3.1) will fix it. Haven’t had the problem occur yet since the update.

 

[Wileri]

I just updated to 13.3.1 and i'm now getting this issue. It was not there before

 

[Don MC]

My problems started with 13.3.

 

[GeorgeX88]

Same issue here. 14 inch MB pro. Elgato T3 Dock. Happens like every fifth time I start the MB. It goes away when I change the pre settings of the internal display in the display settings. I switch for instance from the Apple XDR Display P3-1600 nits to Apple Dispaly P3 500 nits, and the internal display is back up again. So imo clearly a software / macOS issue.