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Since Windows 7 and Server 2008 R2, it is possible to boot from a VHD (Virtual Hard Disk) file.
Note that you can only boot a VHD which has been created using Windows 7 or 2008 R2 or later, and you must configure the boot loader from an active installation of Win7 or 2008 R2. You can't use Virtual PC VHDs, only Hyper-V or raw VHDs . Don't try to reuse
an existing VHD, start a new one for boot use.
You need to edit the bootloader from within Windows, using the bcdedit command-line tool. To do this follow the steps below:
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If the VHD was used to boot a Hyper-V VM, then the Operating System (OS) installed inside the VHD is configured to boot using default inbox IDE drivers (“IntelIDE”). This might not be the case for the
physical system that you're going to boot. Your physical hardware may require a different driver (either inbox or vendor-supplied) to boot an OS. This is particularly true in case of SATA and/or RAID controllers..
If your hardware requires a custom mass storage driver provided by third-party vendor to boot an OS you need to inject that driver into the OS installed inside the VHD to make it bootable on your hardware.
If you need to undo the operation described above and revert to single-boot configuration.
If you need to perform an opposite convertion operation see How To: Convert a VHD-Bootable Image into Hyper-V VM.