So, you have downloaded 'Developer Preview" of Windows 8. This post walks you through the process of booting off a VHD.
Although, there are various ways to do this, for example you can do it all from the command line using tools like ImageX, DISM, etc, or you can do a lot of it graphically with tools like BellaVista. You can also SYSPREP the VHD directly from the ISO's WIM with IMAGEX if you know what that stuff means. It's a little subtle and requires you go get some tools.
Scott Hanselman in outline the process of using the ISO->USB tool.
Here are the steps:
- Step 0 - Have a lot of Disk Space
Make sure to have atleast 60 gigs. If you don't have enough space when an expandable disk "bloats" itself to the fixed size on boot, it'll blue screen, so expandable or not, have the slack space.
- Make a USB stick or DVD from the ISO
Go get the Windows 7 USB/DVD download tool and get yourself a USB stick with at least10 gigs. Go through the process by pointing at the ISO you downloaded and then preparing your USB key. You can also use the resulting USB key to boot and install Windows 8 from your sacrificial hardware if you like.
- Make a Virtual Hard Drive
You can do this later in the process by pressing Shift-F10 while in the Setup Tool, or do it now from the Disk Management GUI or from DISKPART at the Administrator command line.
Be aware that your VHD needs to be on an internal drive or SATA drive. USB won't work as the drivers are initialized too late in the boot process. Also, if your machine is BitLockered, your VHD needs to be on a non-BitLockered partition and you need to suspend BitLocker during this process.
- Start up an Administrator Console and run DISKPART. Execute the lines after DISKPART> below, changing them for your own system.
- OR do it from the Disk Management GUI.
At this point, you've got a VHD that's empty, but ready to have Windows installed to it. The VHD and your system are NOT ready to be booted from. That will come in a minute.
- Boot off the Windows 8 USB Key
Now, restart your computer with your new USB key plugged in and startup your BOOT MENU. The hotkey is usually F12 to bring it up. You want to boot off the Windows 8 USB key.
Side Note: If you own a Gigabyte motherboard - you need to make sure that you USB key is only plugged into the board directly in the back. Then, don't use the Boot Menu, it never works. Instead, enter the BIOS with the DEL key and manually put your USB Key (it'll be detected by brand, so be prepared to recognize the string) at the top of the Hard Drive boot order.
- Attach the VHD while still inside SETUP
Start the SETUP process, click Install Not but DO NOT PICK A HARD DRIVE. As shown in this screenshot, instead hit SHIFT-F10 to get to a console. Now, attach your VHD and install to That. For this, run DISKPART and selected and attached the VHD with these now familiar commands:
DISKPART> select vdisk file=d:\VMs\Win8.vhd
DISKPART> attach vdisk
Next, ALT-TAB back over to the list of disks and hit REFRESH. You'll see your VHD show up. Mine is the 60 gig one. That's the blank we are going to install to.
Note that installation will warn you that this VHD can't be booted to. Yet. That's cool, go ahead and install to that empty VHD.
At some point it'll ask you to restart the computer. The setup process isn't done yet, but go ahead and reboot and remove the USB key.
Your system should reboot and setup will continue, this time off the VHD.
NOTE: Now, create a BCD entry using BCDEDIT.EXE from an Administrator command line.
Just confirm it with bcdedit.exe /v while running Windows 8 Developer Preview.
Setup completed, and I rebooted again to make sure I could get back into Windows 7.
Now, you are greeted with completely new Windows 8 'boot manager' that you'll see if Windows 8 Developer Preview is the default. Otherwise you'll see the Windows 7 text-mode one first.
[Source: Scott Hanselman]