Frage: imac 27" mid 2010 - backlight random switch off
i installed 10.13.4 on my imac 27" mid 2010 and discover a bug that the backlight switches off at random.
first i thought that my imac was gone and that i have the graphic card problem that many users had. but than i saw that the display is still showing windows and only the backlight switched off. the backlight lights up as soon as you reboot.
than i found a user at youtube that discovered that you can get the backlight back to work without rebooting.
when the backlight goes off just
1. type "cmd-shift-eject" - shortcut for switching off backlight (thou it is already off)
2. wait 2-3 seconds
3. press any key and backlight switches back on :-) until it goes off again :-(
if you set higher backlight levels it switches off in a shorter time, if you set the level less than 50% the backlight stays on (at least for a much longer time period)
i still thought of a hardware error until i discovered that this only happens with high sierra. i tried with 10.6.8 and 10.12.6 - no problem.
so this looks like a new bug in high sierra but do not mix it with graphic cards bug or half lighted displays. this looks to me like a software bug.
every hint is welcome
iMac, macOS High Sierra (10.13.4)