Repair HyperV Machine Boot (VHDX)

Kari
Are you really speaking about rescueing existing OS installation (by re-creating missing system reserved partition and boot loader inside)? Then please describe the mechanism how it works which is unclear & not working on physical hardware and in other hypervisors.
Are you speaking about an fresh install - all the configuration, updates, user accounts, programs etc lost?. If this is the case then please re-read 1st post several times, again and again, there is a chance you understand it.
Thanks again.

@Kari,

Does creating a new VM with an existing .vhdx file recreate the system partition on the virtual hard drive?

Davichin
In the morning I feel my suggestions were a bit over-complicated; the easiest way should be:
- add second vhdx into the same virtual machine
- install win10 on it using ltsc iso
- add bootmenu entry for rescued system using easybcd.
Other steps are unnecessary.

muchomurka said:

Davichin
In the morning I feel my suggestions were a bit over-complicated; the easiest way should be:
- add second vhdx into the same virtual machine
- install win10 on it using ltsc iso
- add bootmenu entry for rescued system using easybcd.
Other steps are unnecessary.

But then you have two full installs of Windows in the same VM and all you are using the second install of Windows for is a boot menu entry to boot the first install.

It would take less than 5 minutes just to recreate a System partition on the existing vhdx drive.

muchomurka said:

Who cares if original installation works but if you really want - optional steps:
- delete boot entry for new installation
- delete corresponding partitions (except EFI of course)
- shrink second vhdx.


I do not know simpler way to re-create efi partition with bcd store which will work with rescued system, maybe someone else.

1) dd just the efi partition to target drive if the data still exists
2) libguestfs can do things with nearly all formats of VM's -- doesn't depend on any specific HOST (or Guest) file system.

However depending on the complexity of the VM and the hardware it's being run on it's probably quicker simply to create a new VM --these days with decent hardware and SSD's re-installing Windows isn't such a tedious chore as it used to be --of course if you have a lot of old software with license keys etc plus need their updates to install as well --and even then some of those companies might not even exist any more then another issue.

Cheers
jimbo

muchomurka said:

Who cares if original installation works but if you really want - optional steps:
- delete boot entry for new installation
- delete corresponding partitions (except EFI of course)
- shrink second vhdx.


I do not know simpler way to re-create efi partition with bcd store which will work with rescued system, maybe someone else.

Hola a todos. Muchas gracias por todas las respuestas y por intentar ayudarme. Muchas gracias.
He probado varias cosas... el resumen es el siguiente.
Estoy con una maquina virtual HyperV de generacion 2.
Archivo de Disco VHDX y GPT.
Ya no existe la particion EFI de arranque .
- Creo una maquina virtual nueva eligiendo como disco duro el que yo tengo pero al no tener la partición de arranque no funciona .
- Creo un maquina virtual con la misma versión de sistema operativo y cuando esta funcional sustituyo el disco vhdx... tampoco funciona

Now I am going to try this ... although I have never used the EasyBCD.

- - - Updated - - -

jimbo45 said:

1) dd just the efi partition to target drive if the data still exists
2) libguestfs can do things with nearly all formats of VM's -- doesn't depend on any specific HOST (or Guest) file system.

However depending on the complexity of the VM and the hardware it's being run on it's probably quicker simply to create a new VM --these days with decent hardware and SSD's re-installing Windows isn't such a tedious chore as it used to be --of course if you have a lot of old software with license keys etc plus need their updates to install as well --and even then some of those companies might not even exist any more then another issue.

Cheers
jimbo

Hi. I did not understand what you meant, but I think you mean what it would be to re-create the boot partition with "libguestfs" although I don't know how to do it.
I have also tried booting with the Windows installation CD to see if it recognizes the installation but when the partition is missing it does not recognize that there is a windows installation and the boot cannot be repaired.