Windows 10: Create a VM from W8.1Pro before upgrading to W10

I have no sources to cite but Microsoft could blacklist the key for both OS's on their server.

 

Yeah, they could. They could also block all the other 5 billion dodgy XP and 7 installs if they felt like it.

I guess they don't want to. I wonder why... Advertising presumably.

 

Thank you for the information on MS licensing. I have the appropriate licenses and if I can get the VM up and running, I have a full blown license of 7, 8.1 or 10 I can use on it but updating the key - so that is not my issue, nor what I asked about.

I was asking about how to make a VM from a physical machine and be able to boot from it. I made the VHDX, I can mount and access that VHDX on another machine. I just can't get it to boot. My suspicion is now that I need to edit the file so that it is looking at the proper place for the UEFI and O/S as per that article in my first post.

I think the issue is I need to edit the file so it looks to the proper location of the UEFI and O/S.

 

that is easy....

Assuming the VHDx file is on a USB and that the VHDx file is being mounted to the USB...

Mount the VHDx

Bcdboot VHDx:\windows /s USB:\

that will write the VHDx Boot files to the drive that is hosting it..

Use the actual drive letters for USB and VHDx

if the VHDx is on the Host PC Drive

then bcdboot VHDx:\windows

to add to host boot menu..

Attachment 83159

Windows 10 VHD added to Windows 8.1 BootMenu - Booting VHD from Data Drive...
Windows 10 got Digitial Entitlement from the Windows 8.1 OS..
Since I can Only Boot and use one OS version at a time - it is legal....

Now if that VHD was portable - the PC that the VHD was booted into would have to have received Digitial Entitlement or windows 10 activation would be knocked out....

the problem with Windows to Go - is you need a volume license... to maintain activation when switching between different PC's

 

No, it is not easy. Well OK it is easy but not trivial.

A VHD (or VHDX) is like any other disk - it can be formatted as either GPT or MBR.

The method is different.

For generation 1:
bcdedit /copy {default} /d "Boot from Foobar.vhdx"
bcdedit /set {guid} device vhd="[D:]\VHDs\Foobar.vhdx" (replacing guid with the generated guid and D with the drive the vhdx is on)
bcdedit /set {guid} osdevice vhd="[D:]\VHDs\Foobar.vhdx"
bcdedit /set {guid} detecthal on

For generation 2:
mount vhdx
bcdboot F:\Windows (replacing F with the drive it vhdx is mounted to)
bcdedit /set {default} description "Boot from Foobar.vhdx"

Normally I would use VHD formatted MBR as it is smaller and faster than VHDX. There arguments to use VHDX instead of VHD (journalling really) but I tent to not bother. I can't think of any reason to make a VM using GPT but perhaps there is a reason I didn't consider.

You are quite right about licensing of course.

 

I think the problem is in Disk2VHD, how it creates the VHD or VHDX file; it for some reason leaves the EFI system partition empty.

It works perfectly when creating a VHD or VHDX from a BIOS / MBR system.

See the screenshot. On the right is the source, an UEFI / GPT machine (virtual) from which I created a VHDX using Disk2VHD. The EFI system partition contains the EFI folder as it should.

On the left is the new virtual machine, created using the VHDX made from the machine on right using Disk2VHD. The EFI system partition is empty.



(Click / tap to enlarge.)

 

I appreciate your helps and want to make sure I understand what you mean, so to clarify:
USB drive is D:, on it resides the VHDX file. When I mount the VHDX file it is mounted as E:

Thus, if I understand you right my command will look like (without the quotes"?
"Bcdboot VHDE:\windows /s D:"

including no space between "VHD" and "E"?

thanks again.

 

Bcdboot E:\windows /s D:

E:\ = VHD File
D:\ = USB Stick

 

Unfortunately it still won't boot as a VM.

I ran the bcdboot command as per above, and it said it succeeded. And it created an EFI directory:




But when I start the VM I still get the message:




In the VM settings here is the boot drive info:




Any thoughts on what I am doing wrong and how to fix it?

 

I suspect that per this article Preparing Virtual Hard Disks for Boot

I need to do one more step - "Use the bcdedit /store <path> option to specify the BCD file inside the VHD as the BCD store,"

Do you agree?
Never mind, that didn't work either.