I'm trying to shrink my VHD from 35G to 25G. I have attach the VHD from my VM host and shrink it down but now have unallocated space (10G). I've search and find that VHDresize will allow me to shrink it to 25G. but when I run VHDresizer, following the steps, the "resize" button is gray out. How can I get it to work?