So, the machine auto-activates Windows 10 Home Edition at install time. No prompts, no nothing. You insert the generic upgrade key, and it throws an unhelpful error message back at you:
Error code 0x83fa067 means exactly the same thing.
This probably surprises nobody, but trying again, as the above message suggests, will not work for you.
The solution? Stuff the install media (in my case a USB stick made with the Media Creation Tool), back into the machine, then run the following command:
setup.exe /auto upgrade /pkey VK7JG-NPHTM-C97JM-9MPGT-3V66T
There’s that generic upgrade key again.
After it’s done updating, proceed as usual.