Restored UEFI-based Windows 2008 R2 SP1 cannot be booted in Hyper-V environment

Challenge

Restored UEFI-based Windows 2008 R2 SP1 cannot be booted in the Hyper-V environment, while the restore operation is performed without errors, the data is accessible

Cause

The boot failure is caused by the general incompatibility of such setup with Hyper-V.

• Windows 2008R2 is supported by the virtual machines of
  Generation 1 only
• UEFI-based boot is supported by the virtual machines of Generation 2 only

Solution

1. As a workaround, it is possible to convert the bootloader from incompatible GPT to MBR. It could be achieved via any liveCD, e.g. via Veeam Recovery Medea. The detailed procedure is outlined here. Thus, the idea is to restore the machine to Generation 1 first and then convert the bootloader to MBR – in this case, both requirements will be fit (G1 + MBR loader on BIOS).
2. Change of the environment from Hyper-V to physical machine or any other hypervisor that does not have such limitations if the scenario allows that.

More Information

https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/plan/should-i-create-a-generation-1-or-2-virtual-machine-in-hyper-v