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You might have read and tried the scripts from my first blog about creating a bootable vhd in Creating a bootable vhd the easy way, and in this blog post I’ll continue where I left with some information about my usage of difference discs and bootable vhd’s.

First of all I started by creating a bootable vhd with my script with the following options:

Name Type Size
Base2k8r2.vhd Expandable 80 000 Mb (Remember that you need this much free space on your disc even if the vhd doesn’t have the size from start)

This left me with a vhd-file that took about 7Gb on my internal disc. I restarted my machine to make sure that my bootable vhd was working correctly.

After the health-check and some customizations like folder options in explorer I opened up a command prompt and entered shutdown /r /f , this way I don’t have to enter a reason to restart my Windows Server 2008 R2 OS Blinkar

Back in Windows 7 I took these steps to create a difference disc to keep my base disc clean:

  1. Start a command prompt as Administrator
  2. Write BCDEDIT /v and hit enter
  3. You will see the boot entries and their GUIDs
  4. Write BCDEDIT /delete {guid to the entry with a the path to your bootable vhd}

    WARNING this will delete a boot entry, make sure you enter the GUID to the entry where the device/osdevice points the path of your bootable vhd. Entering the wrong guid could make your computer UNBOOTABLE.

  5. Write DiskPart and hit enter
  6. Enter _ CREATE VDISK FILE=”<Path to difference vhd>” PARENT=”<Path to parent vhd>“ _
    You must specify a valid folder name or you’ll get an error.
  7. Write SELECT VDISK FILE=”<Path to difference vhd>” and hit enter
  8. Write ATTACH VDISK and hit enter
  9. Write Exit and hit enter
  10. Write BCDBOOT <your assigned drive letter>:\Windows and hit enter
  11. If you write BCDEDIT /v and hit enter you should see a new boot entry that points to your new difference disc.
  12. Restart your machine and make sure that your bootable difference disc starts correctly.

When I get some time I’ll try to automate these steps into a handy batch-file or application. I hope you found this post interesting.