Boot from VHDX for Windows 8.1 Update

You may have seen my previous blogs on how to very quickly make your computer multi-boot into another operating system.

Now that Windows 8.1 Update and Windows Server 2012 R2 Update has been released, I’ll briefly repeat the steps.

  1. Download Convert-WindowsImage.ps1 and copy it to a temporary directory
  2. Start Windows PowerShell ISE in Administrator mode
  3. Run it with .\Convert-WindowsImage.ps1 -ShowUI
  4. Choose the required ISO file
  5. Choose the SKU
  6. Choose the VHD/VHDX Format, Type and Size
  7. Modify the Working Directory if necessary
  8. Type a name for the VHDX
  9. Optionally add an existing Unattend.xml file for further customization
  10. Hit Make the VHD!

You will see

My Windows 8.1 Enterprise VHDX was only 7.6GB small which came as a pleasant surprise.

The VHDX should still be mounted under a drive letter. If not, right-click the VHDX and mount it.
In my case I had ejected the mounted disks and manually re-mounted under drive F:

The following steps are needed to make your computer boot from the VHDX file:

  1. Open an administrative command prompt via WIN+X Command Prompt (Admin)
  2. Type bcdboot F:\Windows
  3. Type bcdedit /v to see the result in the Windows Boot Loader section

Taking the identifier you can change the description in your bootlist by typing:

bcdedit /set {545a3023-1918-11e2-bed1-bd8926e5c774} description “Windows 8.1 Enterprise with Update”

If you had configured Hyper-V on your Windows 8.1 computer, don’t forget to enable the hypervisor launchtype:

bcdedit /set hypervisorlaunchtype auto

1 Comment

  1. Wayne Wisniewski's Gravatar Wayne Wisniewski
    April 24, 2015    

    Every time I try to build my VHDX I receive the following error:
    “ERROR : There is a mismatch between the VHDPath file extension (), and the VHDFormat (.VHD). Please ensure that these match and try again.”
    Can you explain what I need to do?

No Pings Yet

  1. Boot from VHDX for Windows 8.1 Update | hyper-v... on April 4, 2014 at 18:45

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