Question: 27" 5K iMac 2015 severe image retention
Bought a 2015 27" 5K iMac brand new at the start of 2017. Used for a year fine without image retention/burn in on 10.12 Sierra.
Just updated to High Sierra 10.13.3 and now I can't have anything on my display for more than 5 minutes otherwise the image is retained by the display.
Using Windows 10 in bootcamp, I don't get the issue. Even after hours of the display remaining on and everything on screen completely static, no image is retained.
Booting Linux from an external hard drive, I don't get the issue. Same situation as Windows 10.
iMac with Retina 5K display, macOS High Sierra (10.13.3)