Chosen Solution
Hi my iMac is stalling during the startup process. Using any of the following methods the result was the same: progress bar gets to about 30% then stops progressing. It has been left overnight in this state. I have tried from built in HD, external usb HD and yosemite installer on thumb drive. I have succesfully booted a macbook pro using the iMacs built in hard drive in target mode as the startup drive for the laptop. So it does not appear to be a drive issue! In verbose mode starting from recovery partition (on a cloned ext usb hd) it stops at:
In verbose mode starting from tested clone of internal hd it stops at:
Safe mode yields the same result. In single user mode I can run fsck. No improvement. Is this possibly a pram battery issue?
Try running AHT from the original system installation DVD.
