How to use a VHD to dual-boot Windows 8 on a Windows 7 PC

How to use a VHD to dual-boot Windows 8 on a Windows 7 PC

Summary: Updated for Windows 8 RTM and Windows 8.1 Preview: Want to try Windows 8 but don't want to mess up a perfectly good Windows 7 installation? Follow these simple step-by step instructions to to run Windows 8 from a virtual hard disk.

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Update, July 14, 2013: I have tested the steps in this article with the Windows 8.1 Preview and can confirm that the procedures described here work properly.

Update, August 17, 2012: I have tested the steps in this article with the Windows 8 RTM code on multiple test systems and can confirm that everything works just as described here. 

My portable PC of choice these days is an ASUS Zenbook UX31E. It’s a wonderful little machine—light, fast, fun to use, and a great example of what’s right with the whole Ultrabook category.

I wanted to try Windows 8 on this machine, but I didn’t want to mess up a perfectly good Windows 7 installation. This is, after all, a machine I use for work, and Windows 8 is still a new operating system. Before I commit to it, I want to be sure everything works well.

See also:

The Zenbook has a 128GB SSD, which is fine for a secondary work PC but not enough to split in half for a conventional dual-boot setup. And there's no way to upgrade that built-in drive. After a few milliseconds of thought, I rejected the idea of trying to shrink my existing disk partition so I could pull that off.

And then it struck me: Wait a minute. I can boot Windows 8 from a virtual hard disk on this machine! And 30 minutes later, that’s exactly what I was doing.

I still have a single SSD with a single partition. But this is what I see at startup:

The actual steps for creating a virtual hard disk (VHD) and installing Windows 8 on it are very simple. The hardest part, in my experience, is wrapping your mind around exactly how this procedure works. So in this post I’m going to explain everything in detail, in the clearest, simplest language I can. Follow along, and I am confident it will work for you too.

Disclaimer, right up front: This works for me. I’ve tested it on several PCs, and I’m confident enough to write about it. But I haven’t tested it on your hardware. You should make a complete backup of your PC (preferably as a system image) before you try the procedures I describe in this post. In fact, you should have a complete backup of your PC even if you don’t try this. OK?

First things first. To make this work, you need the following ingredients:

  • A desktop or notebook PC running Windows 7 Ultimate or Enterprise (preferably 64-bit). The Boot from VHD feature does not work on other versions of Windows 7. If you’re running Windows 7 Home Premium or Professional, you can’t do this.
  • Windows 8 installation media (32-bit or 64-bit). You can use any edition of Windows 8. If you have a DVD, use it. MSDN/TechNet subscribers can download ISO files from those sites. Microsoft makes a free 90-day trial version of Windows 8 Enterprise available as well. Get details about these options here.
  • The Windows 7 USB/DVD download tool, which is available for download here. (Don’t let the name fool you—it works just fine with Windows 8.)
  • A 4GB (or larger) USB flash drive or a DVD. I highly recommend using a USB flash drive as your installation media. It’s faster, and it works on any modern PC.
  • At least 20GB of free space on a local hard disk or SSD. If you plan to do more than tinker with Windows 8, I recommend that you have at least 60 GB of free disk space, plus enough extra disk space to accommodate a paging file equal in size to the amount of RAM in your PC.

And one extra caution: If you've protected your system drive with BitLocker encryption, stop right now. This will just make you cry.

OK? We good? Then continue...

Download the Windows 8 Release Preview ISO file and use the download tool to make a bootable USB flash drive or DVD:

You are now ready to begin the process of creating a virtual hard disk and installing Windows 8.

Page 2: Creating a virtual hard disk -->

Topics: Operating Systems, Hardware, Microsoft, Software, Windows

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71 comments
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  • Parallels workstation makes it a snap...

    It can do this on any version of Windows 7 with enough memory and disk space. I believe this can happen on Oracle VirtualBox, but have not done this successfully.
    DAMANgoldberg
    • but VHD boot should have better performance

      what with it being a boot image rather than a virtualised image as such...
      mary.branscombe
    • Not the same thing at all

      First, Parallels Workstation costs extra money. This doesn't.

      Second, it introduces additional third-party software into the equation.

      Third, it doesn't allow direct access to hardware, the way Direct Boot to VHD does.

      Virtualization is great for certain scenarios, but Direct Boot to VHD is a much cleaner solution, with fewer complcations.
      Ed Bott
    • Virtual Box is just as good as VMware Workstation

      And it's 100% free (untill Oracle want to start charging for it) :( . Win 8 does not have any VM tools yet, but it runs fairly good considering how clunky the OS is designed. I had at one point both Windows 7 VM and Windows 8 consumer preview, running on Virtual Box on my Mac Mini. Runing both osx and windows allows files to be shared bettween the too via Samba. I can run both Mac apps and legacy windows apps at the same time. But win 8 was so awfull I had to remove it. i would rather put vista VM on it than win 8 any day.
      Bakabaka
  • The reason I went the other direction

    I did the shrink and install route because I didn't want a clean Windows 8 install, I wanted an upgrade install dual booting with Windows 7 (which I haven't needed to go back to yet) - so I shrunk and cloned the 7 partition, but I did put in a larger Kingston SSD to make room
    mary.branscombe
  • I've seen this before...

    Here: http://www.hanselman.com/blog/GuideToInstallingAndBootingWindows8DeveloperPreviewOffAVHDVirtualHardDisk.aspx

    And I'm pretty sure you can do it with Windows 7 Home Premium (that's what I did)
    javierazabache
    • According to the specs...

      Microsoft says the feature is only supported on Ultimate and Enterprise.

      See the Direct Boot from VHD entry in this chart:

      http://windows.microsoft.com/en-US/windows7/products/compare

      As for Scott's post, I have seen it before, along with a dozen other posts that tackle the same topic. This is my independent work and a different presentation. There's plenty of room in the world for multiple people to put their own stamp on ideas.
      Ed Bott
      • Thankfully Windows 8 Pro supports Boot to BHD.

        Thankfully Windows 8 Pro supports Boot to BHD.

        To be clear, Win7 Home Premium and Pro support creating and attaching VHDs but not booting from them.

        Pity, as I wanted to try this simple way to Windows 8 on my Win7 Home Premium PC too.
        bradavon
      • Win 7 Pro

        despite what others are saying I concur with Ed it doesn't work on Pro, you can create and attach the VHD but Win8 'next' box remains greyed out when the vhd is selected for install.
        Jaipo
      • VHD

        Ed, can this be done on a USB Hard Drive?
        txmadmansatx
      • Create the VHD in diskpart...

        When you open diskpart from the win8 installer, create the VHD there. Win7 Pro won't boot from VHD, but your article is not about booting Win7. It is about booting Win8 CP which does boot from a VHD.

        I created and attached the VHD in diskpart. installed with no issues and have a dual boot with Win7 Pro. Only Win8 boots from the VHD.

        Command is: CREATE VDISK FILE="C:\VHD\win8-cp.vhd" MAXIMUM=60000

        In order for that to work, the C:\VHD directory must first exist.

        WIN8 boots to the OS selection screen and then I can select which OS to boot.
        Freddy McGriff
  • And they say Win8 is for Consumers!

    It's nice to see some pretty awesome improvements on the enterprise side of Windows 8. I love all the virtualization support.

    I think they've finally reached a point where it's more beneficial to run apps in a "thin-client" style... virtualized OS image and Remote App setup... than to maintain multiple hardware and software configurations. :)
    GoodThings2Life
  • Windows 7 Recovery Disk/Flash drive for Ultrabooks?

    I'm having trouble getting my HP Folio 13 to properly recognize a recovery CD (created via an external USB CD/DVD drive). I've also tried creating a recovery flash drive but ran into some problems.

    Any tips, resources?
    rorrr
    • You're still under warranty

      I would recommend a call to HP support. My experience with them has been very good through the years. They can walk through a much more sophisticated and relevant troubleshooting protocol than I can.
      Ed Bott
      • Thanks. Tried it again. It worked.

        I simply erased the CD-RW and recreated a system repair disk. Surprisingly, it only took about 10 minutes to restore the image (~40GB).
        rorrr
  • I used VHDs

    I used VHDs for W8DP and W8CP installs.
    I had no problems with the VHDs (well ... I couldn't do an upgrade from DP to CP).

    W8 CP, on the other hand ... :(
    lehnerus2000
  • Dual Boot

    When installing another Windows OS on a Windows system as dual boot, one need not go through the process of restarting the machine, changing boot options, and wait minutes for installation to start. Just boot to your original OS, insert the boot media of 2nd OS, or just open the iso file (on a virtual drive or just extract the file to a folder), and double click the setup.exe file. Yes, you can install Windows just like any other application by double clicking the setup.exe file. You will save couple minutes booting from installation media.
    Raju Das
  • How can I do this?

    How can I do this if I don't have Windows Server 2008 R2
    Don't you need a server and the correct software to create a virtual harddrive?
    jughead4158@...
    • Say what?

      You don't need a server for any of this. The screenshots in this article were taken with Windows 7 Ultimate.
      Ed Bott
  • Thanks Ed

    Worked great. Nice that the VHD has access back to the original drive.
    compsrt