How to unmount a VHD in Windows 7. There is no unmount option

After you attach the vhd, you can remove it by going into disk management and right clicking the left side box of the vhd drive. The left side box is the area that says the Disk name, disk type and size. If you right click white area of the drive, the delete command is grayed out. Let me know if that helps.

In diskmgmt.msc, towards the bottom, just to the left of the drive layout image, where it lists "Disk #", "Basic", etc.... right-click the VHD and select "Detach VHD".