Native booting vhdx file not working

jabbawok said:

I've been trying to native boot Win10 on a vhdx virtual disk. I'm following this guide: You are being redirected....
Everything seems to work as it should. But when I reboot the system the following error is shown:

I'm testing this in a VMWare VM with UEFI boot and Secure Boot disabled. I think it has something to do with the bcdboot command but have no idea how to fix it. Has anyone done this successfully?

Testing in a virtual machine will not work unless the vhdx has boot files.

All you need to do to native boot vhdx file is

1. Boot to Windows.

2. Attach vhdx file from disk management.

3. Note the drive letter of windows in attached vhd.

4. Type following

bcdboot #:\windows

where # is drive letter from step 3.

jabbawok said:

Done all that. The problem seems to be with the vhdx file being located on another drive. It works fine from the primary drive, which is no good for my strategy.

I found a post on another forum where it was suggested to use mount point GUID instead of drive letters in the bcdedit command as the drive letters of other disks may not be assigned at the time. If you can explain how to do that I'd be grateful.

I do it all the time like I said. You have to be booting from windows when running the bcdboot command, not from winpe.

On many pcs, the vhdx file needs to be initialised same as host OS, i.e. both legscy bios or both UEFI. Others are clever enough to handle difference.

jabbawok said:

I've been trying to native boot Win10 on a vhdx virtual disk. I'm following this guide:

The article you linked to is on my own website, written by me. I have also published it as a video on Ten Forums video thread.

jabbawok said:

I'm testing this in a VMWare VM with UEFI boot and Secure Boot disabled. I think it has something to do with the bcdboot command but have no idea how to fix it. Has anyone done this successfully?

jabbawok said:

The problem seems to be with the vhdx file being located on another drive. It works fine from the primary drive, which is no good for my strategy.

I found a post on another forum where it was suggested to use mount point GUID instead of drive letters in the bcdedit command as the drive letters of other disks may not be assigned at the time. If you can explain how to do that I'd be grateful.

jabbawok said:

Thanks. I gave up testing in the VM and just went ahead and did it on the actual laptop. Unfortunately after booting into the vhdx based OS it kept giving WHEA errors. Not sure why that is so I'll have to do some more research.

The two most common reasons for a native boot VHD to fail to boot are 1.) space required, and 2.) trying to boot VHD from removable device or external disk.

First, the space required. When booted to VHD, the space required is the size of the actual VHD file on host, plus the maximum size of virtual hard disk.

An example: a dynamically expanding native boot VHD is stored on drive F:. It's current file size is 20 GB. The VHD size is set to be 50 GB. This means that drive F: must have at least 70 GB free, when VHD is used to boot computer, or it is used on a virtual machine.

This is clearly not your case, because Windows gives a BSOD when trying to boot from VHD and drive has not enough space. According to you, you do not get BSOD.

Second reason is using a wrong disk / drive. A native boot VHD must be stored on an internal hard disk or SSD. It cannot be booted to, if stored on a removable drive like SD card, USB flash drive or on external disk.

The temporary drive letter used when deploying Windows to VHD is irrelevant, as is using GUID instead of drive letter. That letter will not be used. Instead, Windows boot records refer to actual location of the VHD file, as here in my case file VHDTest1.vhdx on my F: drive:



Kari