Chosen Solution
I thought it was a failing hard drive, but replacing the drive after cloning the data didn’t change this behavior. Boots fine from network recovery, but the OS won’t reinstall because whatever OS is on the drive is newer than Lion. Shift-Command-Option boot still gave me only Lion as an install option. Built in diagnostics doesn’t report any trouble. SMC has been reset, as has PRAM. Disconnecting the hard drive cable and attempting to boot from known good OS results in an immediate kernel panic Trying to boot from the cloned drive gets partway through the boot process before rebooting with no message. Swapped out RAM with the same result. What am I missing here? What else can I check?
OK, here is what I did to fix it. The original hard drive was almost 100% full. I think this lead to many of the issues. I’m sure it lead to some amount of data loss through cross linked files or overwritten data. Well, I’m not sure, it’s just that the fix leads me to believe this. Also at issue was the machine had been powered off for a while, used by a non-techie who had no idea of his OS version, and my Known Good Boot Drive (KGBD) being newer than the OS on his machine. The KGBD, having not been created on that model machine, was missing something that did not allow the drive to boot older hardware. What lead to the confusion is that by getting a successful (seemingly) clone of his drive to a new SSD, the SSD had the same symptoms as the original drive - it would reboot in the middle of the boot process. So the 100% full hard drive lead to the corruption that did not allow the machine to successfully boot even from a (seemingly) successful clone. Reverting back to an older OS boot drive allowed me to (first I had to use terminal to delete the /System folder on his machine) install 10.10 on the machine. Anything newer during the install process gave me an error computer is “missing a firmware partition” but no amount of downloading firmware patches from Apple’s web site fixed the issue. I’m willing to bet that 10.11 and newer would install now, although I’ve left that decision to the customer and haven’t heard back yet. Carbon Copy Cloner did not successfully clone the drive, despite getting no errors during the cloning process! A random spot check of the original drive (which was able to be mounted once the computer was brought back to life) revealed obviously missing files and folders from the home folder which lead to my conclusions above.
Are you sure you’ve booted up on your external drive? Did you use the Option key at startup? Reference: Mac startup key combinations Also, did you try replacing your RAM?
