Chosen Solution
Hi there, my iMac suddenly stopped working (no cursor movement, no keyboard feedback, nothing), got stuck and I rebooted it manually. After that, the boot process ends and gets stuck on a completely gray screen, after the startup sound, apple and loading bar. I tried almost all software solutions (NVRAM reset, HD Recovery, incompatible .kext deletion). The only way I’m able to boot the iMac is in SAFE MODE. During summer I noticed some graphic glitches, that’s why I believe the problem is hardware related and caused by GPU or something related to graphic.
Think about it. If it boots in Safe Mode, it’s not a hardware issue. UPDATE: 12-22-15 I looked at your link. They’re guessing. Set up an external startup drive and install a clean system and boot from it. See if the problem persists.
