exporting vhd not allowing us to boot up via vhdx in hyper v

Question

exporting vhd not allowing us to boot up via vhdx in hyper v

Tyler Tomayko 5

Manish Deshpande 1,330 Reputation points Microsoft External Staff Moderator

2025-12-11T19:18:29.5866667+00:00
Hello @Tyler Tomayko

Thank you for contacting us about the Booting issue. We have begun looking into it and will share our suggestions with you as soon as possible. We appreciate your patience while we work on this.

What version of Hyper-V are you using, and does it support all the required features?

Have you confirmed the VHD file is indeed in a fixed size format?

Can you provide the size of your VHD?

Are you encountering any specific error messages when trying to boot up the VHD?

Thanks,
Manish
Manish Deshpande 1,330 Reputation points Microsoft External Staff Moderator

2025-12-16T03:24:48.79+00:00
Hello @Tyler Tomayko

You can try this steps for fix the Missing boot files issue.

1.Create a New Temporary VM
Open Hyper‑V Manager.

Select New → Virtual Machine.

Choose the correct VM Generation:

Generation 1 → if disk uses MBR

Generation 2 → if disk uses GPT/UEFI

Complete the wizard without attaching any disk.

2.Attach the Exported VHD/VHDX

Right‑click the new VM → Settings.

Under storage controllers:

IDE Controller → Gen 1

SCSI Controller → Gen 2

Attach your 127GB VHD/VHDX.

Also attach a Windows installation ISO under DVD Drive.

3.Boot into Windows Recovery

Start the VM.

When the Windows Setup screen appears: Repair your computer → Troubleshoot → Command Prompt.

4.Identify Disk & Partitions : Run the following

1.diskpart

2.list disk

3.sel disk 0

4.list vol

5.exit

Identify:

EFI partition (FAT32, ~100–500MB) → Gen 2

System Reserved (NTFS, ~350–550MB) → Gen 1

OS partition (largest volume)

5.Repair the Boot Loader

Gen 1 VM

1.bootrec /fixmbr
2.bootrec /fixboot

If /fixboot gives “Access denied”, use: (bcdboot C:\Windows /s C: /f BIOS)

3.bootrec /scanos

4.bootrec /rebuildbcd

If its a Gen 2 VM:

diskpart

sel disk 0

list vol

sel vol <EFI volume number>

assign letter=Z

exit

Rebuild the UEFI files
bcdboot C:\Windows /s Z: /f UEFI

6.Run the file system repair using - chkdsk C: /f

7.Remove ISO & Reboot

Shut down the VM.

Remove the ISO from the DVD drive.

Start the VM normally.

Run on the Hyper‑V host:

Repair-VHD -Path "D:\Path\Disk.vhdx"

These steps resolve issues caused by missing boot files, corrupted EFI/MBR, mismatched VM generation, or VHD/VHDX metadata issues.

If the issue still persists please revert back with the error message or snip for reference.

Thanks,
Manish

1 answer

Your answer

Manish Deshpande 1,330 Reputation points Microsoft External Staff Moderator

2025-12-11T19:18:29.5866667+00:00

Hello @Tyler Tomayko

Thank you for contacting us about the Booting issue. We have begun looking into it and will share our suggestions with you as soon as possible. We appreciate your patience while we work on this.

What version of Hyper-V are you using, and does it support all the required features?

Have you confirmed the VHD file is indeed in a fixed size format?

Can you provide the size of your VHD?

Are you encountering any specific error messages when trying to boot up the VHD?

Thanks,
Manish
Manish Deshpande 1,330 Reputation points Microsoft External Staff Moderator

2025-12-16T03:24:48.79+00:00

Hello @Tyler Tomayko

You can try this steps for fix the Missing boot files issue.

1.Create a New Temporary VM
Open Hyper‑V Manager.

Select New → Virtual Machine.

Choose the correct VM Generation:

Generation 1 → if disk uses MBR

Generation 2 → if disk uses GPT/UEFI

Complete the wizard without attaching any disk.

2.Attach the Exported VHD/VHDX

Right‑click the new VM → Settings.

Under storage controllers:

IDE Controller → Gen 1

SCSI Controller → Gen 2

Attach your 127GB VHD/VHDX.

Also attach a Windows installation ISO under DVD Drive.

3.Boot into Windows Recovery

Start the VM.

When the Windows Setup screen appears: Repair your computer → Troubleshoot → Command Prompt.

4.Identify Disk & Partitions : Run the following

1.diskpart

2.list disk

3.sel disk 0

4.list vol

5.exit

Identify:

EFI partition (FAT32, ~100–500MB) → Gen 2

System Reserved (NTFS, ~350–550MB) → Gen 1

OS partition (largest volume)

5.Repair the Boot Loader

Gen 1 VM

1.bootrec /fixmbr
2.bootrec /fixboot

If /fixboot gives “Access denied”, use: (bcdboot C:\Windows /s C: /f BIOS)

3.bootrec /scanos

4.bootrec /rebuildbcd

If its a Gen 2 VM:

diskpart

sel disk 0

list vol

sel vol <EFI volume number>

assign letter=Z

exit

Rebuild the UEFI files
bcdboot C:\Windows /s Z: /f UEFI

6.Run the file system repair using - chkdsk C: /f

7.Remove ISO & Reboot

Shut down the VM.

Remove the ISO from the DVD drive.

Start the VM normally.

Run on the Hyper‑V host:

Repair-VHD -Path "D:\Path\Disk.vhdx"

These steps resolve issues caused by missing boot files, corrupted EFI/MBR, mismatched VM generation, or VHD/VHDX metadata issues.

If the issue still persists please revert back with the error message or snip for reference.

Thanks,
Manish

Answer 1

Tyler Tomayko 5

127GB - hyper v manager - machine wont boot

Manish Deshpande 1,330 Reputation points Microsoft External Staff Moderator

2025-12-15T02:44:55.4733333+00:00

Hello @Tyler Tomayko

Thanks for sharing the details also Could you kindly provide the error message or a screenshot here for reference?

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exporting vhd not allowing us to boot up via vhdx in hyper v

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