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

Tyler Tomayko 5

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

Manish Deshpande 8,135 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 8,135 Reputation points Microsoft External Staff Moderator

2025-12-17T02:10:04.07+00:00

Hello @Tyler Tomayko

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.
Manish Deshpande 8,135 Reputation points Microsoft External Staff Moderator

2025-12-18T05:08:04.2133333+00:00

Hello @Tyler Tomayko

I wanted to check if my last response made sense. I’d be glad to assist further or explain anything in more detail and please accept as Yes and upvote if the answer is helpful so that it can help others in the community.

2 answers

Tyler Tomayko 5 Reputation points

2025-12-11T20:40:24.6266667+00:00

127GB - hyper v manager - machine wont boot
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Manish Deshpande 8,135 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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Manish Deshpande 8,135 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.
1. Select New → Virtual Machine.
2. Choose the correct VM Generation:
  
  Generation 1 → if disk uses MBR
  
  Generation 2 → if disk uses GPT/UEFI
3. Complete the wizard without attaching any disk.
2.Attach the Exported VHD/VHDX
1. Right‑click the new VM → Settings.
2. Under storage controllers:
  
  IDE Controller → Gen 1
  
  SCSI Controller → Gen 2
3. Attach your 127GB VHD/VHDX.
4. Also attach a Windows installation ISO under DVD Drive.
3.Boot into Windows Recovery
1. Start the VM.
2. 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.
1. 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
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