I have been having monitor problems-flickering, black screen, etc., and it's an old monitor, so I contacted Apple and was advised to try Safe Mode to see if the problem persisted. Result: Safe Mode seems to have cured the problem, mostly. Now that I know that, what do I need to do in Normal Mode to get rid of the problems? It's a good monitor, but I bought it in 2016.
Mac mini 2018 or later
does it happen with other monitors?
try resetting your SMC and repeat this step 2 more times, then reset the PRAM 3 times, instructions for both are in this link.
https://support.apple.com/en-us/HT201295
safe mode is going to disable system extensions except for the core ones so it could be a video extension which may or may not point to a damaged video hardware.
Also reset the display to defaults and/or try a different cable from the mini to the display.
does it happen with other monitors?
try resetting your SMC and repeat this step 2 more times, then reset the PRAM 3 times, instructions for both are in this link.
https://support.apple.com/en-us/HT201295
safe mode is going to disable system extensions except for the core ones so it could be a video extension which may or may not point to a damaged video hardware.
Also reset the display to defaults and/or try a different cable from the mini to the display.
Did you install any drivers for that monitor, however ill-advised? These drivers would not be loaded in Safe Mode and may be causing the screen aberrations in normal boot mode because they are not compatible with the current operating system.
Safe Mode also clears System caches, and possibly there was some corruption there impacting your monitor, and a normal reboot from Safe mode may correct the display issue.
Thank you both for the information. The safe mode restart seems to have done away with the problem, like the corrupted system caches referred to just above. At any rate, it seems to be working fine now. No flicker, no black screen. As if I solved the problem by trashing the prefs. I hadn't installed any drivers, and only one of the two monitors was giving me any trouble, so I'm back in business. But I will keep in mind the suggestion to use safe mode and then reset the PRAM-which I have used, but not in a long time. Thank you both for the help.
Safe mode solves a problem-what now?
