I've tried: restarting; resetting the PRAM; Big Sur 11.4 up to date; ran Disk Utility - no issues;
Flickers at approx 6 secs, and blacks out briefly at 8 secs...
Suggestions/ fix please...
Included link to video, first post didn't show up, looks like it did this time!
https://www.hooliganunderground.com/IMac-Screen-Flickers/n-s4s98R/
iMac 27″, macOS 11.4
Hi there rich56kk,
We'd like to help look into what's happening in those videos you sent.
As it's flickering and turning black quickly after waking it from sleep, we agree, this isn't expected behavior.
We recommend following the steps under 'If the display is flickering' in this link: If your Mac display doesn’t look right
If the issue remains, we recommend contacting Apple Support here: Get Support
Take care!
2019 27" iMac Flickers upon Wake up (amended with video)
