Convert a Windows Installation into a unRAID (KVM) Virtual Machine

Because I was turning my Windows 10 Pro server into an Linux (unRAID) machine I already had a Windows installation running on the bare metal that I had spent a fair bit of time setting up. I didn’t want to lose that installation and the work put into it. So, rather than starting over with a fresh Windows installation I took the operating system that was already installed, copied it, and started running it as a virtual machine (VM). Here are the steps I took to convert that Windows installation into a functioning VM.

Most of these steps come from the well-written unRAID Manual on Physical to Virtual Machine Conversion – the main thing I add in here are the Windows-specific steps for reducing the size of the virtual machine image.

They’re also useful for anyone running KVM as a hypervisor – not just specific to unRAID.

Before you begin

  • Makes sure you have access to your Windows license. If you upgraded from Windows 7 or 8 to Windows 10 for free this is really important. If you haven’t already, follow the steps here in “Before you shutdown Windows”.
  • Your hardware must be capable of processor virtualization (Intel VT-x or AMD-V), and it must be enabled in your BIOS. Depending on what you plan to do with your VM, you may need to meet other hardware requirements.
  • unRAID must have VMs enabled and configured. An important step here is to download the VirtIO Drivers ISO
  • unRAID needs to have User Shares created to hold the virtual machine images; by default, these are created for you by a new installation at /mnt/user/domains/
  • Check to make sure that your User Share (above) has enough room for the full size of your Windows Operating System hard drive. You’re going to copy the entire hard drive including the empty space.

By default, most of these things were done already on my machine, but it’s good to check them before proceeding.

If you’re unfamiliar with unRAID and how to take those steps, they are described in the “System Preparation” section of the unRAID manual quite well.

Add a new Virtual Machine

From your unRAID web UI (e.g. http://tower), perform the following steps.

  1. On the VMs tab, click the Windows 10 template (or template for your version of Windows).
  2. Click on the switch for the Basic View to toggle it to the Advanced View (in the upper-right corner of the screen) if it isn’t already set.
  3. Configure the VM with the following settings:
    1. Name your VM whatever you wish: For this example, I’m using “Windows 10”
    2. CPU Mode: Host Passthrough
    3. Logical CPUs: However many you wish (at least one)
    4. Initial Memory / Max Memory: at least 2GB is recommended
    5. Machine: i440fx-* (whatever the newest is)
    6. BIOS: SeaBIOS
    7. Hyper-V: Yes
    8. OS Install ISO: Leave empty
    9. VirtIO Drivers ISO: Select the virtio-win*.iso that (should have been) downloaded as part of enabling VMs on unRAID.
    10. VirtIO Drivers CDRom Bus: IDE
    11. Primary vDisk Location: Auto
    12. Primary vDisk Bus: IDE
    13. Primary vDisk Type: raw
    14. Primary vDisk Size: 0G (You’ll be overwriting this file in the next step)
    15. Graphics Card: VNC
    16. VNC Video Driver: QXL
    17. VNC Password: Set it if you’d like – this is how you’ll access the ‘screen’ of the running VM
    18. VNC Keyboard: Set to the right language for your OS
    19. Sound Card: None (or select one if your device supports passthrough)
    20. Network MAC: this is set randomly, though you can change it.
    21. Network Bridge: br0
    22. USB Devices: I recommend leaving all unchecked for now.
    23. USB Mode: 2.0 (EHCI) is what I found worked for me.
    24. Other PCI Devices: I recommend leaving all unassigned until you confirm the VM launches correctly.
    25. Uncheck Start VM after creation
  4. Hit Create.

Copy the OS Drive to an image

Next up, you need to copy the data from your OS drive to an virtual disk image that the VM can boot off of.

  1. Identify the disk that contains your Windows Operating System. You can find it by looking in the unRAID web UI in the Main tab under Unassigned Devices. Look for the drive that you booted windows off of before you installed unRAID. Make note of the disk id (e.g. sdb, sdc, sde, etc.)
  2. SSH into your unRAID system as root. By default unRAID doesn’t have a root password, but you should have set a strong one by now… right?
  3. Enter the following command to convert the physical disk
    qemu-img convert -p -O raw /dev/sdX /mnt/user/domains/Windows\ 10/vdisk1.img
    1. Replace sdX with the drive id for your Windows OS installaton
    2. Replace Windows\ 10 with the name you gave your Virtual Machine (if you need to see what it is run the ls /mnt/user/domains command to see what it’s name is on disk)
  4. Wait. It’ll take a while, assuming you have a reasonably large OS installation disk.

Start your Windows VM & Install the VirtIO Drivers

Because Windows is now running as a Virtual Machine on KVM, it will think there is new “hardware” and will require (and benefit from) having the right drivers installed.

  1. In the unRAID VMs tab, click on your newly created VM and click Start
  2. After the VM has started, you can VNC into the machine and interact with it. You can do this one of two ways.
    1. Click on the running Windows VM and select “VNC Remote”
    2. (Preferred) Install a VNC client like TightVNC and connect to the VM directly. To do so, you’ll need to know the IP address of your server and connect to the VNC port of the VM (which is listed next to the running VM)
  3. In Windows File Explorer, navigate to the VirtIO virtual CD-Rom (likely disk D:\)
  4. Navigate to Balloon > w10 > amd64
    1. Or your specific version of Windows and Architecture
  5. Right click on the .inf file (i.e. balloon.inf) and click install. (You may need to enable the viewing of file extensions to find the right file)
  6. Repeat the above process for each of the following folders
    1. NetKVM
    2. vioserial
    3. viostor
  7. You may want to check Windows Device Manager to make sure there are no devices which have yellow warning exclamations next to them – if so, you’ll likely need to install an additional driver.
  8. When done with the driver installation, navigate to the guest-agent folder and double click on qemu-ga-x64.msi to install the QEMU/KVM guest agent.

Shutdown the VM & update disk settings

Now that you know that the VM boots and you’ve got the drivers installed, you can stop the VM and update the physical disk to use the VirtIO bus which will give you better performance.

  1. Stop the Windows VM. You can do this one of two ways – one, by initiating a Shutdown from within Windows. Or, you can click on the VM image in unRAID and select Stop which will also gracefully shut down Windows.
  2. In the unRAID web UI, in the VMs tab, select the Windows VM and select Edit
  3. Change the following settings:

    1. Primary vDisk Bus: VirtIO
    2. VertIO Drivers ISO: delete the entry
    3. Restart the VM and make sure it’s operating correctly.

Reactivate your Windows license

Windows checks it’s license validity based on your machine’s hardware. Any time you change the hardware, Windows needs you to reactivate your license. You’ll need to run through the activation steps in the VM to re-activate your Windows license because Windows will think you just changed a lot of hardware.

To do that, search for “Activation” from the Windows 10 Start menu. From there, you should be able to follow the prompts to activate your copy of Windows. Somewhere along the way, in smallish font, it’ll ask you if you recently changed hardware. Click that option and go from there – i.e. log into your Microsoft Account, select the machine/license associated with this Windows installation.

(Optional) Remove Unneeded Software & Drivers

Because your old Windows machine had a lot of device specific drivers installed on it to operate on your hardware, you may have a lot of cruft that can now be removed. Log into your Windows machine and take a stroll through the “Add or Remove Programs” menu to see if there’s anything that can be removed. For me, I could uninstall any Intel and RealTek Drivers, ASUS motherboard features, etc. that were no longer relevant. It’s a nice thing to slim up the now VM’d Windows OS.

(Optional) Optimize the Window VM

The unRAID wiki has a good set of steps to consider to optimize your Windows VM. I personally don’t believe in disabling the search indexer, but most of the other tips are worth while.

(Optional) Reduce / Shrink the size of the VM image

Now, you’re probably saying to yourself… geez, I don’t need a XXX GB image file that just happened to be the size of your old OS hard drive just to run Windows. You probably want to slim that down. Here’s instructions on exactly how to do that.

Let me know if I missed anything here.

8 thoughts on “Convert a Windows Installation into a unRAID (KVM) Virtual Machine”

  1. Pingback: How-to: Migrate from Windows RAID to unRAID – Kevin's Blog
  2. I followed these instructions exactly. Everything worked great until I got to the “Shutdown the VM & update disk settings” part. I made all the changes and installed all the drivers in the same order you specified. However, when I restart the VM as noted in step 3 of the
    “Shutdown the VM & update disk settings” the vm does not work properly. Windows attempts to boot up then goes to the troubleshoot/repair menu.
    I did make the VM with OVMF instead of SeaBIOS for the BIOS option. That is the only thing I did that deviated from your instructions. I don’t think that would cause the issue I’m seeing as it is able to boot up fine with the E drive drivers, it is only when it is switched to theVirtIO drivers that it has problems. I quadruple checked Device Manager and there are no driver issues either. Do you have any suggestions on how I can get this working?

  3. Have you tried switching the BIOS? That’s really the only suggestion I’ve got. I haven’t done this for a long time so I don’t have much advice to give other than that. Please report back if you figure it out.

    1. I attempted to create the virtual machine with SeaBIOS. The machine hangs on “booting from hard disk…” I booted from the same image file I created from your above steps. I attempted to boot with VirtIO and another time with the virtio-win-0.1.160-1.iso file. In both instances they hung at the same point.

  4. Dustin, I have just had the same issue. I converted my old SSD of my Windows Server OS into a img file following this guide. I was also stuck after changing back to the VirtIO vDisk Bus, as my VM crashed on boot with the usual inaccessible boot device error reminiscent of converting IDE to SATA back in the mid 2000’s.

    I tried adding a second vDisk using VirtIO and leaving the boot disk as SATA. This allowed the VM to boot same as the previous step as the primary disk was still set to SATA. I was able to go into disk manager and initialise the second vdisk and format it. I shut down, and changed the primary vDisk to VirtIO and it booted up successfully this time. I was also able to remove the second tempoary vDisk with no issues.

    In my experience Windows can be a bit weird about pre-loading drivers it thinks it doesn’t need, so I think that adding a second vDisk to the OS while the primary disk is running in SATA or IDE mode, makes Windows realise the VirtIO driver is necessary.

    I’m using Q35-4.1 and OVMF for the VM

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