macOS Tahoe not waking Extended Display

I have the same issue. Mac mini M4 Pro with two monitors connected via USB-C directly to the Mac mini. Prior to the upgrade this configuration was working absolutely perfectly. Since upgrading to Tahoe only one monitor will connect when waking the Mac from sleep (although both monitors do wake/connect occasionally - maybe 5% of the time).

One monitor always connects. The second monitor appears to connect but then displays a “no signal” message. If I switch this monitor off using the power button and back on again, the monitor connects and I get a display on both monitors. If I switch either one of the monitors off and then wake the Mac the display appears on the monitor that is switched on. If I then switch on the second monitor then it connects and I get a display on both monitors. Have tried every setting in macOS and the monitors. Tried every sequence of powering on devices, and tried every sequence of unplugging and plugging in again - both power and USB cable - on all devices without success. Have also tried swapping cables and replacing cables.

As mentioned, there were no problems with this configuration prior to the upgrade to Tahoe. Nothing was changed to my configuration prior to the upgrade.

TheSuperTrain wrote:

I have a setup with a Mac mini connected to two external displays, each via their own thunderbolt/usb-c cable. I recently upgraded to macOS 26 and just started experiencing an issue where on wake, only the "Main Display" would actually connect to the display (the other "Extended Display" receives no input). The only way to fix the issue is to manually unplug the thunderbolt cable to the extended display and plug it in again, at which point it connects.

Is anyone else experiencing such an issue, or have a solution?

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External displays is a bit of a mess in Tahoe in my experience. I have a PowerBook M4 Max that never had any issues with external displays before upgrading to macOs 26.

Main issues are tv-s through hdmi do not connect, or take a lot of fiddling and switching resolutions etc to get working.

Sidecar, which I use a lot on the road to have a mobile secondary display through my iPad doesn't connect directly anymore, won't show up in display settings. Sometimes iPad shows up in the menubar item, but only to control with keyboard and mouse. If I do that I can then change to extended display in system prefs.

The connection also isn't as stable as in the previous OS.

Hope they fix this soon

I just want to add to this that I am having an identical issue. I have 2 monitors, primary connected with USB-C and a secondary by HDMI. Without fail, every time my M4 Mini Pro goes to sleep, only the HDMI monitor wakes up. And it's particularly frustrating because that is a 24" display flipped vertically, and when it wakes up the resolution is not oriented properly. So I also have to unplug cables to get the right display back online.