Solved: “The unsigned image’s hash is not allowed (DB)”

In this post, we will go through steps to fix “The unsigned image’s hash is not allowed” error that shows up in certain situations while using Hyper-V.

Virtualization enables IT professionals to easily build and scale client and server environments. The software called “hypervisor” is used to create and manage virtual machines. Hyper-V (formerly known as Windows Server Virtualization) is one of the most popular and robust hypervisors.

Once you create a virtual machine (VM), you will need to install an operating system (OS) in order to use it for any business or personal purpose. Operating systems can be installed in virtual machines via network, ISO file or DVD drive.

When I tried to install Windows Server 2008 R2 into an Hyper-V virtual machine via an ISO file, I received the following error message in booting screen.

3. SCSI DVD (0,1) The unsigned image’s hash is not allowed (DB)

Hyper-V error: The unsigned image's hash is not allowed. Solve "unsigned image's hash is not allowed" error
Hyper-V error: “The unsigned image’s hash is not allowed”

The solution for “The unsigned image’s hash is not allowed” error

The reason Hyper-V doesn’t allow you to use the selected ISO is that it doesn’t trust this file. In order to prevent the system being hijacked at boot time, Hyper-V allows using only the authorized images (ISOs).

Good news! Even though your ISO is not authorized, you can still use it. You need to disable “Secure Boot” by following the steps below.

  1. In Hyper-V Manager, make sure the virtual machine is turned off
  2. Select the virtual machine. Right click and select “Settings” 
  3. Go to “Security”
  4. Uncheck “Enable Secure Boot”
  5. Restart the machine and try to boot from the ISO file
"Enable Secure Boot" option. Solve "unsigned image's hash is not allowed" error
“Enable Secure Boot” option

After successfully installing OS, I would recommend enabling the “Secure Boot” back.

Trying to downgrade OS or disable “Secure Boot” in UEFI? Check this post out.

Thank you for this StackExchange post.

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