Hello everybody! I have an issue with booting iMac A1419. Progress bar stop on half, sometimes appears green or blue colour on the screen like on photo. Even if I can easily turn it on, the computer works well for several days, until I turn it off. I wonder if this is a problem with the graphic card?
I agree with BDAqua's assessment, it sounds like a gpu failure. It's impossible to accurately diagnose hardware failures on a message board though so I'd recommend a trip to the nearest Apple Store genius bar or AASP to have the iMac checked out.
Does the iMac boot properly in Safe mode? Use safe mode to isolate issues with your Mac - Apple Support
Hook up a second monitor and see if it does the same thing on it.
That is mostly a sign of GPU failure, about halfway through the heavy duty Graphic drivers load that use all the VRAM & video Card attributes.
Yes, in safe mode everything is OK.
Good advice Mike.
I reinstalled Catallina then Mojave but nothing changed.
iMac A1419 booting problem
