I closed the industrial software last night. I detached the VHD. The host machine rebooted into Windows 11, where the weather widget in the taskbar asked me to "Finish setting up my device."
Booting VHDs natively vs. hypervisor-hosted
: Obtain a legitimate Windows 8.1 ISO image from the Microsoft Software Download Center .
Since official pre-configured VHDs (like the old evaluation images) are no longer hosted, the first step is to download the standard installation media.