How to dual-boot Windows 10 Insider Preview using VHDX

If you like to test drive the Windows 10 Insider Preview, but you don’t want to create a virtual machine and you don’t want to modify your current installation, you could instead create a virtual hard drive (VHD) to dual-boot your system alongside another version of the operating system.

Believe it or not using a virtual hard drive to dual-boot Windows 10 Insider Preview is more flexible that running a virtual machine, because technically once you finish configuring the operating system there is not virtualization involve and Windows 10 will take full advantage of the hardware. Also, it’s a better option over installing the operating system on top your current installation, as it’s a pre-release version and it is buggy and features aren’t fully implemented.

Now in this guide you’ll learn how to use the Deployment Image Servicing and Management (DISM) to apply the Insider Preview image to a virtual hard drive, so you can then dual-boot with previous versions of the operating system, including Windows 7 and Windows 8.

Important: This method is only supported on Windows 7 and later versions, and on hard drivers that aren’t using BitLocker. Also if you’re following this instructions on a Surface Pro 3, you better download drivers pack before proceeding.

How to dual-boot Windows 10 using VHDX

Download the ISO file of Windows Insider Preview and extract all the files into a folder.
Open Disk Management, click Action, then Create VHD. Use the VHDX file format and assign how large your virtual hard drive should be.
Find a location to store the new VHDX (preferable choose the “C:\” location), pick a descriptive name, click Save and then OK.
When the virtual hard disk has been created… From the Disk Management, initialize the new disk. Right-click the new drive, select Initialize Disk and GPT, and click OK.
Right-click the unallocated disk space and select New Simple Volume, click Next, Next, make note of the new drive letter, click Next, leave the default settings, click Next, then Finish.
Open the Command Prompt as an administrator and move the Sources directory where you extracted the Windows Insider Preview ISO file. Below there is an example.
```
E:\Windows10InsiderPreview\Sources
```
Run the DISM (Deployment Image Servicing and Management) command to apply the install.wim image to the new virtual hard drive. Type the following command and hit Enter:
```
dism /apply-image /imagefile:install.wim /index:1 /ApplyDir:E:\
```
Where “E” is the drive letter you assigned to the new virtual hard drive.
After the DISM complete applying the image to the new virtual hard drive. The next step is to make the new drive to be recognized by the bootloader. To do this, in Command Prompt type the following command and hit Enter:
```
bcdboot E:\Windows
```

Finally restart your PC and from the bootloader choose the Windows Insider Preview and the operating system will boot as if it was a new computer that is booting up for the first time. You’ll then need to complete the installation process as you would in a new PC.

Once you’re in desktop, make sure to connect Windows online to get the latest updates and necessary drivers. If you’re using a Surface Pro 3, you may not be able to connect online due to the fact that the wireless drivers didn’t install during the setup process. Here you’ll have to get online and download the Surface Pro 3 drivers pack.