Do you know that the VHD file will expand to the size of the partition inside the VHD when you boot into it?

When preparing a Boot to VHD image it is important to know the size of the partition which is setup inside the VHD file – you should make a note of this when you create the VHD image. The reason for this is because the VHD file will expand to the size of the partition INSIDE the VHD.

For Example:

• A Windows installation called WindowsInVHD inside the VHD file has a partition size of 60GB.
• It is copied to the D:\ drive of a laptop called Frog and only takes up 10GB of space (as it is a dynamic expanding VHD).
• When you boot into WindowsInVHD (the VHD sitting on Frog’s D:\ drive), the VHD file expands to 60GB - the partition size of ** WindowsInVHD. **
• This means you will need at least 60GB of free space on Frog’s D:\ drive free

If you do not have free space equal to the size of the partition inside the VHD image, you will get a blue screen telling you that you are out of hard drive space.