This one took me a while to figure out, and maybe I’m just bad at searching online, but the “answers” I found were infuriating nonsensical. I just wanted to install Windows on a MacBook Pro.
Error message from the Windows Installer:
Windows could not prepare the computer to boot into the next phase of installation.
This was because the boot media I was using had an EFI partition. I’m not clear on its purpose since it was empty, but removing fixed the issue. I’m installing “by hand”, since I can’t get Boot Camp Assistant to work - I even reinstalled MacOS and reset the NVRAM.
I have no idea what is up with this. Most of the time it fails with
-2100F, but every now and then when I’m not looking, it’ll work. I thought it might be the pi-hole, but I’ve seen it work with the denylists enabled.