We have a few Windows 8.1 systems here that are currently configured to Native Boot from a VHD file. I'm trying to upgrade these systems to Windows 10, but it looks like it is not possible to update Windows on a virtual hard disk. I've read that one way to get around this is to create a VM in Hyper-V, attach the VHD file to the VM, update Windows through the VM, and then copy the new VHD file back to the host system, however I'm running into an issue when trying to boot the VHD in Hyper-V. I attach the VHD file, boot into a Windows 10 installation .iso, go into Command Prompt, and write the boot files using C:\Windows\System32\bcdboot C:\Windows /s C: where C: is the Windows partition. When I reboot the VM, I get a Virtual Machine Boot Summary stating that The boot loader did not load an operating system, and A boot image was not found. The VHD is GPT partitioned, so no need to mark it as Active. This is the first time I'm trying to do this, so let me know if I've forgotten a critical step in this process... or if there's an easier way to go about this that doesn't involve Hyper-V. All suggestions welcome ! Thanks.