Rebuilding: New Hyper-V Host VHD(X)s Not Working

I'm upgrading and replacing hardware/ software with a new Hyper-V host and I have a new, 750GB RAID 5 Vol called "GuestVol" .
I have a couple of VMs that I really want to reuse so I copied their VHDs from the old RAID1 Vol (which is scheduled to be removed) over to GuestVol. I would like to go with all Gen 2 VMs but I know that Gen 2 does not support .VHD so I used disk edit to convert to VHDX but I keep getting the same error:
Boot Failed EFI SCSI Device
I know if this were a physical disk I could just boot to BIOS and turn off the EFI but thats not the case here.
Am I stuck with GEN 1 or is there a solution?
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Cliff GaliherCommented:
You can't just change a disk to VHDX and boot it in a gen2 VM. The disk won't have the necessary UEFI boot code, and a ton of internal integration code in the OS besides. If you want Gen2, you have to install the OS fresh.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
A_AmericanELectricAuthor Commented:
Thanks Cliff. Please look back on that last thread before I close it.
VB ITSSpecialist ConsultantCommented:
Do you still have access to the old virtual machine, including the necessary configuration and VHD files? If so have a look at this tool which can convert your Gen 1 VM to a Gen 2 VM:

Note that you'll obviously need to run this script on a 2012 R2 Hyper-V host.

If the old host is running 2008 R2 and below, please be advised that you cannot simply export the VM then import the VM into a 2012 R2 Hyper-V host any more as Microsoft have made some changes to the WMI namespace. Here's more information if you're curious as to why:
Active Protection takes the fight to cryptojacking

While there were several headline-grabbing ransomware attacks during in 2017, another big threat started appearing at the same time that didn’t get the same coverage – illicit cryptomining.

A_AmericanELectricAuthor Commented:
I think I can get this. I placed the script in a folder- C:\script

I have confirmed that it will run Gen 1

PS C:\script>Convert-VMGeneration.ps1 -VMName "APLUSSERVER-3" -Path E:\APLUSSERVER-3 -VHDXSizeGB 80

So this will give me a APLUSSERVER-3 Gen2 in the same directory?
VB ITSSpecialist ConsultantCommented:
It should duplicate the VM and append (Generation 2) to the files and folders of the new Gen2 VM.

Is the OS of the VM that you're converting running Windows 2012, 2012 R2, Windows 8 or Windows 8.1? If not then the VM won't work as Generation 2 VMs must be running these OS's.

Here's why 2008 R2 and Windows 7 VMs aren't supported as Gen2 VMs:
Why are 64-bit versions of Windows Server 2008 R2 and Windows 7 not supported as generation 2 guest operating systems?

Although Windows Server 2008 R2 and Windows 7 support UEFI, they depend on a programmable interrupt controller (PIC), which is not present in generation 2 virtual machine hardware.
A_AmericanELectricAuthor Commented:
2012 R2
A_AmericanELectricAuthor Commented:
There is a little bug in the script.
I just got back in the next day to find powershell still on "preparing image" .
I had to hit the enter key while on the PS window to get it to go to "applying image"

Do you happen to know how long it usually takes with good hardware resources?
A_AmericanELectricAuthor Commented:
Please check this out guys
ID: 28541193
VB ITSSpecialist ConsultantCommented:
Depends on how large the VM is. I didn't have to wait too long for a 2012 R2 VM with a 80GB VHD file.

Please check this out guys
ID: 28541193
Sorry but what is this ID number for specifically?
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Windows Server 2012

From novice to tech pro — start learning today.