Using an "undo" disk on Virtual PC 2007, when the VPC is shut down, the program will ask, "Do you want to merge the change into the main virtual hard drive, or discard the change, or to save the change into a separate file".
But on Windows 7's Virtual PC, I tried using the same images as above, from the website
but this time, when I shut down the virtual PC, there was no question asked. The undo file (.vud) keeps on growing each time I boot up and shut down, and the original .vhd remains intact. Is there something that can be done to merge, or discard those changes? The .vud file is now about 1.2GB large.
Update: seems like no one knows an answer yet?