C:\Program Files\Oracle\VirtualBox>VBoxManage.exe modifyhd "c:\Users\gebruiker\VirtualBox VMs\ubuntu mini\ubuntu mini.vbox" --resize 40000
VBoxManage.exe: error: Could not get the storage format of the medium 'c:\Users\gebruiker\VirtualBox VMs\ubuntu mini\ubuntu mini.vbox' (VERR_NOT_SUPPORTED)
VBoxManage.exe: error: Details: code VBOX_E_IPRT_ERROR (0x80bb0005), component MediumWrap, interface IMedium, callee IUnknown
VBoxManage.exe: error: Context: "OpenMedium(Bstr(pszFilenameOrUuid).raw(), enmDevType, enmAccessMode, fForceNewUuidOnOpen, pMedium.asOutParam())" at line 179 of file VBoxManageDisk.cpp