You probably already know that the Windows 10 Technical Preview is out and available for download. If you like trying out the latest and greatest from Microsoft, and can deal with some bugs, installing it now will give you an opportunity to familiarize yourself with it before it is released. You’ll even have an opportunity to provide feedback, and help shape the next Windows operating system.

 

If you are like me, you may want to try it out, but don’t have an extra machine laying around. Virtual machines won’t give you the full immersive experience. But you probably don’t want to potentially damage your existing work or home rig either. You also may not want to run a Technical Preview as your full time Operating System on your production work or home machine.

 

There’s a great solution. Recent versions of Windows have the capability of booting to a VHD file residing on your current hard drive. This is a great feature, it can allow you to run a full Windows installation temporarily, using native hardware, with little to no performance loss.

I’m going to step you through installing the Windows 10 Technical Preview on a virtual disk VHD file, and then configure your Windows 8 workstation to boot directly to it without risking your current operating system.

Disclaimer
This procedure assumes that you have some proficiency with the command line, Hyper-V, disk architecture, and the boot process. We are changing boot options, formatting volumes, and installing operating systems. Everything you do here is at your own risk. Please make sure you know what you are doing, and that you back up all your data and settings before proceeding. This has been tested on Windows 8.1 Pro and Enterprise, and should work on Windows 7 with some modification.

 

Step 1: Create a VHD
Open an elevated command prompt, and run the following:
diskpart
create vdisk file=C:VHDWin10.vhd maximum=25600 type=fixed
select vdisk file=C:VHDWin10.vhd
attach vdisk
create partition primary
assign letter=v
format quick label=vhd
detach vdisk
exit

Step 2: Install Windows on the VHD
If you don’t have the preview, you can get it from here: http://windows.microsoft.com/en-us/windows/preview-download
Note – using Hyper-V is beyond the scope of this post, but the following step identify the basic steps needed.

Open Hyper-V, and create a new virtual machine
When selecting the Hard Drive, browse to the newly created VHD
Once created, specify the media, browsing to the Windows 10 Preview ISO
Boot the new VM, and install Windows 10
Perform the initial login of Windows 10
Shut down the new VM of Windows 10 Preview

 

Step 3: Deploy the VHD with Native boot capabilities
Open an elevated command prompt, and run the following:
diskpart
select vdisk file=C:VHDWin10.vhdx
attach vdisk
list volume
select volume <volume_number_of_attached_VHD>
assign letter=v
exit
cd v:windowssystem32
bcdboot v:windowsdiskpart
select vdisk file=C:VHDWin10.vhdx
detach vdisk
exit

Step 4: Boot to the Repair Console to boot to Windows 10
From the start menu in Windows 8

Open PC Settings
Select Update and Recovery
Select Recovery
Select Restart Now

After restarting, you’ll have the startup boot menu

Select Use another operating system
Select Windows Technical Preview
This will boot you into your new Windows 10 Technical Preview. Now you can test drive Windows 10, and get a head start on learning it before it is deployed in later in 2015!

References