Windows 10: Reusing vhdx (native boot) in Hyper-V

Hey all,

I created a .vhdx in disk management, initialised, new volume and formatted.

Deployed Win 10 Insider 17754 to it using dism /apply-image etc. Updated the bcd store on main OS, booted to .vhdx natively no issues.

Now since MSoft doesn't allow the upgrade to newer builds for vhd's I wanted to attach the .vhdx to a virtual machine in Hyper-V (on my main install obviously) and then perform the upgrade process.

Tried creating a gen 2 machine, attached the .vhdx, didn't boot. Tried attaching an .iso of the Win10 install also, still didn't boot.

Created a gen 1 machine, with both .vhdx and .iso attached, it booted from the .iso but said no disk drive was detected/installed.

I tried using the repair computer option, setup couldn't repair it, so loaded up command prompt used diskpart, it picked up the drive, marked the current partition active, and tried to manually enter the following commands:

bootrec /fixmbr (successful)
bootrec /fixboot (fail) said something like access denied
bootrec /rebuildbcd (success)

Restarted the VM in Hyper-V still not booting from the attached .vhdx nor did the install from .iso detect the drive either.

Any suggestions as to how I can boot from the vhdx and upgrade the windows installation to build 17760 and then reuse the same .vhdx to boot natively?

Regards

:)

 

Can't native boot Hyper-V generation 2 vhdx


If I create a generation 1 VM I can native boot the vhdx by adding bcd entry. If I make a generation 2 VM it fails with "a required device isn't connected...0xc0000225". Pressing f8 for "Startup Settings" gives "The application or operating system couldn't be loaded because a required file is missing. File \Windows\system32\winload.efi. Error code 0xc0000225"

This is my BCD entry Code:

Code:

Windows Boot Loader  -------------------  identifier              {default}  device                  vhd=[D:]\Hyper-V\Windows-vm3\Virtual Hard Disks\Windows-vm3.vhdx  path                    \WINDOWS\system32\winload.efi  description             Windows-vm3  locale                  en-US  inherit                 {bootloadersettings}  recoverysequence        {2bd3faf9-6091-11e5-86c4-c3a22c898ce3}  recoveryenabled         Yes  isolatedcontext         Yes  flightsigning           Yes  allowedinmemorysettings 0x15000075  osdevice                vhd=[D:]\Hyper-V\Windows-vm3\Virtual Hard Disks\Windows-vm3.vhdx  systemroot              \WINDOWS  resumeobject            {2bd3faf2-6091-11e5-86c4-c3a22c898ce3}  nx                      AlwaysOn  bootmenupolicy          Standard  hypervisorlaunchtype    Auto

and the Hyper-V definition (I've tried with and without secure boot, changing the boot order and removing the separate pagefile drive. It always works on Hyper-V will never boot on native boot.





Conversely if I install windows and turn off the VM before the first reboot I can boot it natively but Hyper-V will not boot (again complains of missing bootloader). The bootloader can't be repaired by bootrec, no valid windows installations are found.

Windows versions I'm using are 10 Pro build 10240 for host, build 10586 or 10240 for guest.

Does anyone know if it is possible to native boot a generation 2 VM vhdx and boot it through Hyper-V, the same as you can with generation 1?

 

Hyper-V - Native Boot VHD  

Hello Ryan, welcome to Ten Forums.

A VHD or VHDX file can be serviced offline. Fast and easy way for you to get drivers installed would be to follow instructions in this tutorial: DISM - Add or Remove Drivers on an Offline Image

Export your existing drivers from host, including SSD drivers as told in Step Two in above mentioned tutorial (you can skip Step One), then follow instructions told in Steps Three, Four and Five.

Not only do you get all drivers injected to your VHD / VHDX but you also speed up its first native boot significantly because all drivers are already installed.

 

Hyper-V - Native Boot VHD  


Kari, Thank you for the awesome post!
I have been native booting VHD and VHDX files for years! I have used this for my previous Laptop but this new laptop has a SSD and I usually have to add the SSD driver during windows install, but by installing in Hyper-V I didn't get the driver installed.
I have tried installing the driver in Hyper-V but I still can't get the VHDX file to Native boot.
Any direction or recommendations would be appreciated.
Thank you,
Ryan aka