How to resize a VirtualBox vmdk file

source https://stackoverflow.com/questions/11659005/how-to-resize-a-virtualbox-vmdk-file  Resizing with the command vboxmanage modifyhd Machine-disk1.vmdk –resize 30720 gives the error Progress state: VBOX_E_NOT_SUPPORTED VBoxManage: error: Resize hard disk operation for this format is not implemented yet! you …