It's said that VirtualBox's VBoxManage modifyhd --resize command can only be used on either VDI or VHD files. Sadly, I have a VirtualBox image that is in VMDK format, and I don't know how to convert it to those other two formats.

  • Is clonehd not an option for you? Aug 15, 2011 at 11:31
  • If it converts to VDI, it is.
    – tshepang
    Aug 15, 2011 at 11:32

2 Answers 2


You can use a two-step procedure then - first, use the clonemedium command to create a VDI image:

VBoxManage clonemedium disk aaaa.vmdk aaaa.vdi --format VDI 

(Have a look also at other options to clonemedium, like --variant. To read the help, just run VBoxManage | less or visit https://www.virtualbox.org/manual/ch08.html#vboxmanage-clonevdi).

Once you have the .vdi file, you can proceed with your modifications.

  • This even works if the VMDK file points to (parts of) a raw disk image (as created by VBoxManage internalcommands createrawvmdk).
    – krlmlr
    Oct 23, 2014 at 15:59

If you would like to convert only the virtual disk, not entire VM, you can also use qemu-img for Windows: it's free, portable and it runs under command prompt.

VirtualBox, VMware, Hyper-V disk image types are all supported.

For example, to convert VMDK to VHDX:

qemu-img.exe convert FileSource-Image.vmdk -O vhdx FileDestination-Image.vhdx

Extracted from: http://www.sysadmit.com/2016/08/vmware-convertir-vhdx-en-vmdk.html

  • Thank you. This is exactly what I needed. QEMU is great since it is installable cross-platform too. Oct 8, 2018 at 14:00

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