Was the NUC selected as the HDMI input when it was powered on and booted? If not, you might see some strangeness onscreen. What you are seeing on the TV is likely a TV-specific artifact, however. Try, from powered off state, to boot the NUC while it is selected as the input on the TV.
Hi and thank you for the answer.
If I reboot I can’t see anything on the screen Even the bios screen (the one that shows F2, F10 etc.) isn’t visible.
The system boots up but I can access It only via Remote Desktop.
If I set to boot in safe mode it goes back to normal (even if some screen flickering and artifacts are present now and then), but if I switch back to normal boot the hdmi output is unavailable (Black screen with some lines at the top).
I tried to update the hdmi bios but it’s already the last version I think. I tried also to disable hdmi CEC in bios but nothing changes.
Do you think I may have a defective unit?
UPDATE: I did some more tests and with two other tv there was no output via hdmi with windows started normally.
Then I tried to reinstall the graphic drivers and the output came back! Now I’m leaving the nuc up and running and wait for something to happen. Do you have a benchmark test that can stress the video output to be sure nothing is wrong with my machine?