UPDATE: iMac early 2008 (8.1) ATI HD2400 video card problem

[dreamscape]

Hello. Initially, the iMac had El Capitan installed. The boot process stopped with a white screen. After further investigation, I down graded from El Capitan to Snow Leopard. When the install finished, the iMac hung with a white screen and dozens of black squares all over the screen. I then booted the iMac into safe mode removed the ATI kexts and rebooted. The desktop came up and I logged in.

In summary, in the releases of OSX I’ve tried, all of them had problems with loading the ATI HD2400 kexts. No problems when booting in safe mode with no vga kexts. The iMac hangs when pushed by the ATI kexts.

The video card is an ATI HD2400. It seems the video card is bad and needs to be repaired or replaced.

I tried booting the iMac from a gparted disc with no problems.

Can someone confirm a bad video card could cause this problem?
Thanks

 

[Cory Cooper]

Hello,

-From your description, that sounds like an iMac (20-inch Early 2008), correct?
-I assume you have a Time Machine or other backup of your data?
-Did you add any third-party RAM?
-Have you tried this: How to use Apple Hardware Test on your Mac?

It could be a bad video card, or other hardware issue.

C