Failed in Safe_OS phase error during BOOT operation

0xc1900101 - 0x20017

I'm trying to do an in place upgrade from Windows Server 20012 r2 to Windows Server 2016.  Both Datacenter editions.  Neither are evals or previews.

Now, Win2k12r2 runs just fine.  But when I try the in place install; after the first re-boot, I'm greeted with a blue screen then the error in a window I mention above.

I've removed all 3rd party drivers and all roles except WSUS. 

I've read all over the internet on how people have dealt with this on Windows 10, but not a peep on Windows 2016.  Am I the first one?

Anyone got any ideas?

Thanks.

-Michael.