Chosen Solution
Hello everybody! I am desperate for answer, since I am struggling for days now… I have iMac 27" late 2012, i5 3,2GHz So,my problem: On boot shows kernel panic, or double panic. AHT shows no troubles. When I try Recovery ( CMD+R) , loads internet recovery and then freezes on apple logo, cant get to Utilities to repair disk. I tried new ram, new ram and new HDD at the same time, always the same. Only thing I suspect now is either bad PSU or CPU. Can anyone please help me? Thank you!!
First return the machine to its original configuration. Changing hard drive can bring on a whole new set of issues. You have to be able to get to Disk Utilities to format the drive. Since the old drive is already out use an external enclosure or adapter and hook it up to another Mac and do your repairs there. Once you have a known good drive and system (that you have booted from on the other machine), you can install it and see if you have issues. Do one upgrade at a time, solve any problems like run away fans first, then go for the upgrade.
Hold down Command-V on startup to boot into Verbose Mode, and take a note of where the iMac hangs or freezes during bootup. This may shed some light into the cause of the kernel panics.
