I have performed this action several times with windows server 2003 guests in our environment. Remove the drive, add it to another guest, expand the space in vc or by running vmkfstools, login and extend using diskpart. Occassionally, diskpart will throw an error and not expand the disk (new space is visible in disk manager). The only way I was able to resolve it was to attach it to a windows 2000 guest and run diskpart from there. Anyone know why this would work sometimes and not others?