Why is my iMac 27" display showing black and flickering?
iMac screen would turn black and start to flicker and I can not see or do anything on it.
If I use Thunderbolt to HDMI cable it shows everything on my hd TV, but the iMac screen itself is just black.
Also for example: If I'm playing music and it blacks out, the music continues to play, just can't see anything.
On an external display I can work on it, don't know if it's some kind of GPU issue or the screen itself.