virtualbox.org

How to shrink a .vhd with VirtualBox 4.2 RC4 on OS X 10.8?

Without the need of Wine and CloneVDI.

Look into the Manual. Topic "VBoxManage". Dont know the exact chapter. But it needs tools like "sdelete" running before in the guest to zero free space.

Better use CloneVDI. Its much faster and there is nothing to do in the guest. Result is a vdi file. But i think that is no problem for VBOX