macOS High Sierra (10.13) Upgrade Fails With Endless Kernel Panic Loop
Sorry for the lack of specificity, but I finally was able to get macOS High Sierra (10.13) installed on my Mac mini (Late 2012; 2.5 GHz Intel Core i5) with 16GB of memory and an internal disk that is a plain hard disk drive; not an SSD.


I reset the System Management Controller (SMC).
I reset the NVRAM.
I disconnected all USB peripherals—including a simple/small unpowered USB hub—except for a direct connection between keyboard and mouse and the system.
I then ran Onyx and cleaned all caches—“System” and “User”—before launching the “Install macOS High Sierra” installer.


Crossed my fingers, let it do what it had to do and lo and behold… Everything went as expected!

The only hint of something I noticed before doing this—that might help someone—is I had a bootable USB backup of my main system disk attached during the last failed attempt to upgrade and—this is important—it didn’t seem like I had an explicitly selected startup disk set. The system seemed to just always default to my internal hard disk drive, but never explicitly had that set. I made sure to set that after I reset the SMC and NVRAM. Like I said, not 100% sure that is the cause but it is something to keep in mind.