Boot Camp install failure: inaccessible boot device

I'm setting up a brand new 15" 2019 MacBook Pro for a daughter who needs Windows for some school work. The machine is a beast, with a 1TB SSD and 32GB RAM (she's an architecture student).

I setup macOS just fine, and ran BootCamp to install a freshly downloaded ISO of Windows 10 Pro 1903. I configured it for a 50/50 split of the internal drive, so each OS gets approximately 500GB. Nice, huh?

Important note: I set this up with File Vault for regular disk encryption. I didn't think that would affect Boot Camp, but who knows.

Windows seemed to install nicely until I got to the BootCamp tools. That installation started, then the screen went completely blank. After determining that it was totally unresponsive, I restarted the Mac with the power button. Windows fails to boot, displaying an "inaccessible boot device" stop message. It then automatically restarts and Windows says it is "preparing automatic repair". At that point, it displays (on a blue screen, of course) a list of keyboards to choose, but that's it. I can't select anything, it doesn't do anything. Stuck.

Now what? All suggestions welcome.

1. Is File Vault a problem?
2. Is Windows 10 1903 a problem?