I have a hunch that Steve2926 has hit the target in his post above where he points that BCD might be the culprit here.
E.g., here's the internal disk layout of my Windows 10 VHD, automagically created with VirtualBox under Linux, which boots fine placed on a MBR disk.
![[Image: winvhd.png]](https://i.postimg.cc/023ZPp9K/winvhd.png)
That "System Reserved" partition is in fact the EFI boot store and it becomes active only after Ventoy successfully boots the VHD -- prior to that the main boot store is Ventoy's own "VTOYEFI" partition present in the physical boot drive (also hidden).
I have gone the VHDX path before, since my go to recipe for installing Windows 7 in a virtual disk apparently didn't work any longer with 10 -- and, at first, everybody just said it couldn't even be done.
Bear in mind that, should you decide to try it, you'll be restricted to VHDX under mandatory GPT formatted drives and the new UEFI booting scheme
This absolutely won't work with MBR style drives. I have had nothing but endless grief trying to juggle those restrictions under Windows.
E.g., here's the internal disk layout of my Windows 10 VHD, automagically created with VirtualBox under Linux, which boots fine placed on a MBR disk.
That "System Reserved" partition is in fact the EFI boot store and it becomes active only after Ventoy successfully boots the VHD -- prior to that the main boot store is Ventoy's own "VTOYEFI" partition present in the physical boot drive (also hidden).
I have gone the VHDX path before, since my go to recipe for installing Windows 7 in a virtual disk apparently didn't work any longer with 10 -- and, at first, everybody just said it couldn't even be done.
Bear in mind that, should you decide to try it, you'll be restricted to VHDX under mandatory GPT formatted drives and the new UEFI booting scheme
This absolutely won't work with MBR style drives. I have had nothing but endless grief trying to juggle those restrictions under Windows.