No display on reboot/ startup

[russell_314]

When I restart my 2018 Mac mini sometimes the Samsung CF391 32" monitor won't work properly. Let me explain

I press the power button and the Apple logo and progress bar shows up on the monitor. Then the monitor goes off and has the flashing blue light like it's on standby as if the computer was off. The mini has the normal solid white light. I was forcing shutdown to fix this but now I realized if I unplug the HDMI cable from the mini and plug it back in the monitor turns on.

It doesn't happen every time but maybe half the time. Is this something wrong with my monitor, my mini is glitching, or maybe a software problem?

 

[Stephen.R]

It’s a somewhat common phenomenon apparently. I have it with a 2018 Mac mini and two Dell displays. I find it’s always on a cold boot, not restart.
[doublepost=1559638006][/doublepost]On and I connect the displays via DisplayPort to a TB3 > dual DP adapter, so it’s not hdmi specific

 

[Fishrrman]

Been seeing the same here, usually after a restart, but once in a while after a cold boot.
2018 Mini, 10.14.5. Connecting via HDMI.

It looks like the signal to the display gets "interrupted", perhaps at the point where something software-related to the graphics is concerned "gets loaded", that creates a momentary "cutoff" of the connection between the Mini's "video out" and the display's input. The display goes dark (either "to sleep" or perhaps just loses its input), and then can't "re-sync" to the Mini's output.

A power down (to all the way off) and reboot seems to "get it back".
Or... I can reach behind the Mini, disconnect/reconnect the HDMI, and it comes back in a few seconds.

 

[Stephen.R]

I’m curious is this is at all related to FileVault (which is known to cause issues with eGPU powered displays).

I have FV enabled.

 

[Duncan68]

I have noticed the same thing on my mini. I have no eGPU and have the monitor connected via HDMI.

Powering down the mini and doing a cold boot or unplugging/replugging the HDMI cable brings the monitor back up.

 

[russell_314]

I’m curious is this is at all related to FileVault (which is known to cause issues with eGPU powered displays).

I have FV enabled.

No FileVault here. I read it slows things down a little bit. Also no eGPU.