Sunday, 13 December 2009

Windows 7: Boot from VHD

Recently I have been forced to look into available options to best utilise the amount of memory available on my laptop to be able to run SharePoint 2010 VMs. There are number of options available to do this, but I have tried to simplify this as much as possible to speed up the VHD file creation and imaging process.
1) Create a partition to store the VHD; optional (I had to do this since my primary partition is BitLocker encrypted)
2) Download the VHD tool box from
This tool box includes:
  • WIM2VHD.wsf – WIM to VHD Converter
  • ImageX.exe 64-bit (32-bit available from
  • Bcdedit.exe- Command-line tool for managing BCD stores
  • intlcfg.exe - The International Settings and Configuration tool (Intlcfg.exe) is used to configure the language and locale settings in a Windows image
3) Copy the Install.Wim from the OS media to the VHDToolBox folder
4) Now you are ready to create your VHD. Start command prompt and navigate to the VHDToolBox folder and run the script:
There are a number of switches you will need to know:
/wim: specifies the path to the WIM file
/sku: OS version (ServerStandard, Ultimate etc…)
/vhd: specifies the path and the name of the VHD to be created
/size: specifies the size of the VHD in MB
/disktype: specifies the type of disk, Dynamic or Fixed
For example to create a Windows Server 2008 R2 Enterprise VHD on a 40GB Fixed disk we would use the following command:
cscript wim2vhd.wsf /wim: C:\VHDToolBox\install.wim /sku:SERVERENTERPRISE /vhd:F:\2K8_R2_SP2010_01.vhd /size:40960 /disktype:Dynamic/Fixed
Note: to find the sku you could run the following imagex command on your install.wim file:
Imagex /info “<install.wim location>”
5) Next you need to use bcdedit.exe to add an entry to the boot menu:
  • bcdedit /copy {current} /d "My New VHD Description" (This will Return the GUID of the Loader Object that you will use to replace <guid> below)
  • bcdedit /set <guid> device vhd=[driveletter:]\<directory>\<vhd filename>
  • bcdedit /set <guid> osdevice vhd=[driverletter:]\<directory>\<vhd filename>
  • bcdedit /set <guid> detecthal on
That’s it, enjoy

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