That's fine and dandy for those who want to mount future Windows Operating systems, but what about legacy OS' like windows XP or Windows Vista?

I am thinking that the boot manager itself has the capability of mounting the vdisk and if that's correct, then mounting any pre-existing Virtual Disks you have with an Operating system installed on it, would start that operating system?

Have you tried mounting a Windows Vista VHD using bcedit and seeing if it will boot? Or a Windows XP?

I have been trying for some time to get it right, but no luck thus far. When your in the host operating system (Windows 7) can you run bcedit and post what the entries are to give me an idea of where I may be going wrong?

ok great! thanks. well looking at the vhd entries, it seems that everything I had was correct, the only difference though, was the identifier it is using. It seems that it is using the same identifier for all the entries including your host machine, where my vhd identifiers were different from the host OS. Maybe that is where i went wrong, or perhaps using an identifier of {legacy}, which *should* tell the bootmanager that the VHD contains a legacy bootmanager.

but then  when it comes to the following:

path                    \Windows\system32\winload.exe

systemroot              \Windows

I am confused if that is pointing to the physical disk or to the file / directory within the VHD.

Hi Dennis,

Nice write-up, pretty appreciated. But you were a little vague on how to copy the bootloaders from the Windows 7 DVD to the local drive and activate them for an existing Vista install.

For example I copied the files as you wrote above, renamed the old C:\bootmgr and C:\Windows\System32\bcdedit.exe to *_old; copied the Win7 bootmgr to C:\ and the bcdedit.exe to the system32 folder.

On running the new bcdedit (ver 6.1) got the error that the version of bcd editor will not work on the current OS (freely quoted here of course).

It seems to therefore that your solution could only work in a Windows 7(ver 6.1) installed environment instead of the Vista(ver 6.0) environment. Or do you have another angle to solving this problem. Thanks for your information.

Message truncated above:

On running the new bcdedit (ver 6.1) got the error that the version of bcd editor will not work on the current OS (freely quoted here of course). Rebooting did not solve the problem

It seems to therefore that your solution could only work in a Windows 7(ver 6.1) installed environment instead of the Vista(ver 6.0) environment. Or do you have another angle to solving this problem. Thanks for your information.

Much to my embarrasment, discovered I got your name all wrong, should have written Eric instead of Dennis, very sloppy of me. My sincere appologies.

Hello, Eric!

Nice news. I was thinking about attaching the Hyper-V or Virtual Server's VHDs to my test Windows Server 2008 R2 system setup. The reason is, I don't plan to include the R2 machine into the production environment. However, I would like to test some real-life application that I am running there in R2 environment.

What would be the proper command to do that and include the VHD entry into the boot menu?

I tried the follwowing command.

bcdedit /create /d "Windows Testbed" /application osloader /inherit device /device vhd=[d:]\vhd\customenv.vhd

but all that to no avail.

What am I doing wrong? The VHD file contains a boot partition with opearating system and my custom applications.

Thank you.

I'm still not clear on how useful this vhd stuff is. To make use of it you would need to start with Windows 7 so you can create VHD's. Operating systems before windows 7 do not recognize vhds, so one could not install the os' to these. So there's no benefit in that. I've seldomly used Virtual PC so I dont know if VHD's are created with it when installing virtual operating systems, so there's also no benefit in having windows xp/vista/server VHD's. Lets say VPC makes vhds from Virtual Operating system installs, well that's time well wasted installing the os in a vpc, then complicatingly modifying the boot loader by hand to recognize the VHD as a bootable operating system.

So at least in my eye's, it's wasted time, complicated with very little benefit. Especially if this were incorporated or "sold" as a business/corporate feature.

What about an arugument about Operating system portability because it's a VHD? Well that can be thrown out the window as well, until there is a dynamic boot loader, a dynamic device manager (like Linux live disks) or VHD booting capability within the bios, it will be impossible to hook up an external hard drive to a PC and boot a VHD without touch the files and disk on that particular computer.

Unless there is something i'm missing, I just cannot see the value in this feature they implimented.

Hi Eric,

Do you have an angle for resolving the issue I mentioned above? Thanks already.

Hello Eric,

I found the following problems:

- Surface is not working ==> BCDEdit gives the following alternative: ATTACH      - Attaches a virtual disk file.

When I Attach the VHD and try to install I receive the error that installing to VHD is not supported.

Trying to install: Windows 7 Enterprise Edition Build 7000

Have you tried this?

Regards,

Bas Steelooper

Bas, it works with Windows 7 Enterprise Edition Build 7000.

You are right, you have to use 'Attach' instead of 'surface'.

I got similar error than you, but than you just need to create a partition and format it. Than you can install it. It properly worked for me using Windows 7 Enterprise Edition Build 7000.

Cesar de la Torre

Eric,

In your instruction you say:

Bcdedit /set {GUID} device vhd=[C:]\vhd\2k8toy.vhd

Bcdedit /set {GUID} osdevice vhd=[C:]\vhd\2k8toy.vhd

In your bcd-dump it says:

device file=[C:]\vhd\2k8toy.vhd

osdevice file=[C:]\vhd\2k8toy.vhd

Notice the difference between the word after device & osdevice (file vs vhd)

When I use 'vhd' the Boot Manager gives me an error when I start the machine regarding some invalid information in the Boot Configuration Data store.

When I use 'file' Windows 7 start from the vhd, but after 20 seconds I get a BSOD with error 0x0000012F and the message "An initialization failure occured while attempting to boot from VHD"

It seems that the "repair"-option is only available for drives that are not protected by BitLocker. Mine is. What can I do to "repair" the temp settings?

Eric, you say "at least Now I can have portability of my system", but that's not really true is it?  Since it's booting the VHD now rather than running it virtualized, you require all of the unique hardware drivers in the VHD now as opposed to just the VM enlightenments don't you?

When the VHD isn't being booted, the virtualized hardware works, and is what enables the portability, but when you boot it, it's no longer portable as best I can surmise.

Good article.

Has anyone figured out how to get a legacy OS to boot off a VHD?

I know you can't INSTALL to a VHD from a legacy, but I have been experimenting with pre-existing VHD's that I made up in Virtual PC.

For instance, I have a pre-existing VHD with XP on it, but I can't seem to get it to boot using the above BCDEDIT method. I suppose it has something to do with the boot loader methods, as XP uses "\ntloader", and Windows 7 seems to use "\Windows\system32\winload.exe"

See right now, I am dualbooting XP and Windows 7 from seperate drives, and when I look at the entry for XP I see this:

Windows Legacy OS Loader

------------------------

identifier              {466f5a88-0af2-4f76-9038-095b170dc21c}

device                  partition=E:

path                    \ntldr

description             Earlier Version of Windows

Most likely it's ignorance on my part, as I have not played around with the bootmanager in Vista at all, so I don't know a lot of the commands. I just can't seem to figure out how to get my XP VHD to have similar settings though.

So I imagine it WOULD be possible to boot from a VHD with XP (or any other legacy OS for that matter) wouldn't it?

______________________________________________________________

As far as the usefulness goes, once the technology gets honed out, this could actually change the dynamics of partitioning. Think about it, if you want to set up a beta OS, or even check out a linux distro and only have one hard drive, but it's plenty big, then you just use a VHD. As it stands, the OS takes up the whole hard drive unless you partition in advanced. Or you have to use an extra program to play around with the partition setup like Partition Magic.

IMO simply booting from a VHD can simplify all this. Granted the process of setting up a bootable VHD needs to be simplified, but this is just in the making.

I fixed the BSOD by creating a fixed size vhd instead of the (default) dynamically expanding vhd.

Was type=fixed always in your manual? If so, why did I skip that part?

Yesterday night I discovered a quicker/easier way to accomplish a VHD-boot.

Later in the evening I read a thread somewhere that confirmed my findings.

----------------------------------------------------------------------------------------

Boot your machine from the Windows 7 DVD/USB

At the install screen press Shift-F10 to get a command prompt

Type 'dir' to see which drive letters are assigend and where your vhd should go

diskpart

create vdisk file=c:\vhd\win7.vhd type=fixed maximum=40000

select vdisk file=c:\vhd\win7.vhd

attach vdisk

exit

setup

----------------------------------------------------------------------------------------

So no need to create a boot entry before starting the installation and no need for cleaning up the boot configuration database afterwards.

Eric (and those that also think all the above is cool stuff), on the Microsoft forums I've posted a solution to also boot from a differencing disk:

http://social.technet.microsoft.com/Forums/en-US/winserverhyperv/thread/c7189892-ba70-4348-a952-79c50317ecc9

Have fun rebuilding your machine, let us know when (and how) the project is finished ;-)

Can anyone move the vhd file to an external drive and boot from there?

Very nice post, I was successfully able to boot from a Windows Server 2008 VHD using this approach. I, then tried to boot my XP vhd but could not succeed. For this, I made a copy of my existing WinXP option in and changed "device partition=C:\" to "device vhd=[E:]\myxp.vhd". It, however, loads my real XP when I select this WinXP VHD boot option. Is it possible?

Larry, I tried booting from a vhd placed on an external USB-HDD, but I didn't succeed. I can remember reading somewhere that for now booting is only supported on internal fixed disks.

I successfully Installed Windows 7 build 7000 in a VHD file

along side my XP x64 installation

XP was already installed

I booted from the Windows 7 DVD

opened a CMD prompt

created and mounted a fixed VHD

Installed Windows 7 to it.

Now I'm wondering what if I tried the same time with Vista x64... would it work?

Or what if with 2 DVD drives, one with Windows 7, the other with Vista

I boot from the Windows 7 DVD, create an other VHD the same way I did before

and then instead of starting Windows7 Setup... I strated Vista's setup....

would that work?

I'll be trying this later tonight....

Thankyou, My computer goes very slow when running win 7 in vpc so that is a GOOOOOD idea

To those interested in creating native VHDs on systems such as Windows XP, Windows Server 2003, Windows Vista, etc...Take a look at this utility. This takes all the work out of setting up a dual-boot VHD environment and manages it as well.

www.portlock.com/.../leap_frog