The usual wisdom is to not use macOS betas so I resisted the temptation of updating to Sequoia Beta, but then I inadvertently launched the 14.5 Sonoma update… just to find that my Mac mini wasn’t working as the screen was black and the display (Samsung Smart Monitor M7) had gone to sleep. I thought it was totally bricked until I tried an HDMI cable I had hanging around and it worked fine. Turns out the Display was recognised through USB-C (I could see it connecting the display via HDMI and USB-C at the same time and setting the screen to use the HDMI input) but the computer wasn’t sending any signal.
Turns out this not new but what I find most baffling is the solution:
Physically remove power to the display. Let it stay a couple of minutes. Turn on again. And voilà, it works again.
Does anyone know why this happens?