Chosen Solution
The internal hard drive has been removed. Machine passed AHT extended diagnostic test. Can boot into internet recovery. Whenever I attempt to boot into an OS on an external drive it is unable to complete the progress bar. It just holds the Apple logo with a progress bar that freezes about two thirds of the way in. I’ve tried multiple different forms of external media and nothing works. I tried to boot into a drive in verbose mode - the process hung after listing about 10 lines of “fInterfaceSnapshot is missing“. Does anyone have any diagnostic advice?
Are you accessing the Startup Manager via pressing the Option (⌥) key when you start your system? What is your media a USB thumb drive, or a USB HD drive, or a Thunderbolt drive? Reference: Mac startup key combinations
