Convert and Extend VMDK to VDI for Virtualbox on Mac

Shutdown VM, On Mac Terminal, use below command to convert the VMDK to VDI first, then resize to 80000 MB.

alberts-mbp-2:MacOS albertxu$ ./VBoxManage modifyhd /Users/albertxu/Documents/VDI/win7.vmdk –resize 80000
0%…
Progress state: VBOX_E_NOT_SUPPORTED
VBoxManage: error: Resize hard disk operation for this format is not implemented yet!
alberts-mbp-2:MacOS albertxu$ ./VBoxManage clonehd /Users/albertxu/Documents/VDI/win7.vmdk /Users/albertxu/Documents/VDI/win7.vdi –format vdi
0%…10%…20%…30%…40%…50%…60%…70%…80%…90%…100%
Clone hard disk created in format ‘vdi’. UUID: 6941a00d-6634-4ea5-a76c-61b1a7ae7195
alberts-mbp-2:MacOS albertxu$ ./VBoxManage modifyhd /Users/albertxu/Documents/VDI/win7.vdi –resize 80000
0%…10%…20%…30%…40%…50%…60%…70%…80%…90%…100%
alberts-mbp-2:MacOS albertxu$ ls -al /Users/albertxu/Documents/VDI/win7.vmdk
-rw——-  1 albertxu  staff  21478768640  4 Jan 13:46 /Users/albertxu/Documents/VDI/win7.vmdk
alberts-mbp-2:MacOS albertxu$ ls -al /Users/albertxu/Documents/VDI/win7.vdi
-rw——-  1 albertxu  staff  21460156416  4 Jan 13:54 /Users/albertxu/Documents/VDI/win7.vdi
alberts-mbp-2:MacOS albertxu$

On Virtualbox, Change the VM storage to the new VDI file. Start the VM, In Win7 Seachbox, input disk management, or run diskmgmt.msc, Select C: drive, right click, choose to extend volume, it can automatically detect the expandable space, confirm,

Then refresh your c: drive in “My Computer”, it will be in new size.

Note: gparted is not needed to expand the space in this case.