Ok, So my beloved 2012 Mini may be dying? Not sure. At some point, El Cap was updated to the latest version. I went to wake the Mini from sleep (at this time, it was connected to an HDTV via HDMI). There was a frozen Apple icon with a progress bar about halfway through. Several hard reboots and it just would not boot. There was also no startup chime, couldn't get into Recovery. Took the thing apart, placed the OS drive in an external enclosure and tried to boot to that SSD from another Mac Mini - no joy. Tried to re-install El Cap on the SSD (it was in a Thermaltake BlackX USB 3.0 hub thing), but apparently this Samsung EVO 840 didn't like being connected externally, and wouldn't take the OS upgrade. I gave in, pulled both Minis apart and put the suspect SSD into the 2014 Mini. Booted from a thumb drive, reinstalled El Cap over top of my existing install, rebooted, no problems. Took the SSD out of the 2014 Mini, and put the 2012 Mini back together again. Now, when the SSD is in the 2012 Mini, It gets to the Apple boot screen and instant kernel panic, related to the Airport Broadcom drivers, it seems. I CANNOT boot from a USB drive, I cannot do recovery (CMD-R), I tried CMD-OPT-P-R to no avail, and I even held down the D key for the Apple Hardware test. Test came back clean. Attached are screenshots of the kernel panics. I hope someone knows what to do here. My only alternative is to swap the SSD's again and mourn the 2012 Mini quietly. I'd rather have the 2012 Quad core with 16GB of RAM running than this 2014 dual-core Mini. Help???