There are a number of ways to try out Microsoft’s forthcoming operating system such as installing on a spare machine, installing within a virtual machine or dual-booting using a seperate partition or disk to name just a few. Unfortunately most of them have drawbacks; you’re most likely wanting to evaluate Windows 10 on your current hardware which, unless you have an identical spare rules out the first option. Installing to a virtual machine is quick, easy and non-destructive but lacks the native experience, requires software installation and/or specific processor capabilities and incurs a performance penalty. Lastly dual booting from a seperate partition or disk could require hardware changes or the repartitioning of a disk, both of which are not without an element of risk especially considering Windows 10 is currently an unfinished product.
Another alternative is to install Windows 10 to a VHD (Virtual Hard Disk) and boot natively, as if it was installed to a physical disk. The main advantage being that a VHD is self-contained file meaning there are no changes required to your existing hardware or operating system, and that the installation is almost completely native, with just the disk being virtualized.
There are multiple guides on the internet that walk you through creating a VHD and then installing Windows 10 using Hyper-V, then natively booting that disk. This method however may not work or may cause issues with computers with a UEFI BIOS, particuarly those with Secure Boot enabled. The following guide does not rely on this method, and fully supports UEFI and Secure Boot.
Preparing Installation Media
1. If you have not already, Sign up to the Windows Insider Program and download the ISO file for Windows 10 Technical Preview.
2. Either burn the ISO image to a DVD and skip to step 4, or download Rufus to make a bootable USB stick and continue to step 3.
3.Insert your USB stick into an available port and launch Rufus. Select your USB stick in the ‘Device’ list and click the disk drive icon next to ‘Create a bootable disk using’ and select your Windows 10 ISO. Click Start and wait for the process to complete.
Creating the VHD
4. Open Disk Management by pressing + R, typing diskmgmt.msc into the run dialog and pressing Ok.
5. From the Action menu, click ‘Create VHD’. Specify the size, name and location of the virtual disk and press Ok. Make a note of the exact location and name, for example c:\Win10.vhd.
Installing to the VHD
6. Boot from your newly created USB stick or DVD and wait for Windows setup to load.
7. Follow the steps until you are asked ‘What type of installation do you want?’. Choose ‘Custom: Install Windows only (advanced)‘.
8. You will now be asked where you want to install Windows. At this point, we need to mount our VHD so it appears as a possible installation target.
To do so, first press Shift + F10 to open a command prompt window.
Type diskpart and hit enter to load the diskpart utility.
Select your VHD using the path you noted earlier by typing select vdisk file=c:\Win10.vhd and pressing enter.
Attach the VHD by typing attach vdisk and pressing enter.
9. Close the command prompt window (or type exit) to return to the ‘Where do you want to install Windows’ dialog. Your VHD should show just as a physical disk would, and will be available for selection as an installation target. Select it and continue with the Windows installation process.
Once installed you will be able to choose whether to boot into Windows 10 or your existing OS whenever you start your machine.