Not sure where or how I got a VMDK file as a VM, because I usually use VDI’s, but for some reason I had one. Follow this post to expand its disk by converting it to VDI and then expanding it.
In Virtualbox, shutdown the VM and remove the disk from Virtual Media Manager and the VM.
Create a batch file and place as many disk and stuff that you want to convert:
echo "converting to vdi" VBoxManage clonehd --format VDI Z:\virtualbox\yourdisk.vmdk Z:\virtualbox\yourdisk.vdi echo "resizing vdi" VBoxManage modifyhd Z:\virtualbox\yourdisk.vdi --resize 120000
In Virtualbox, re-attach the new disk. Not sure if this will screw with Windows Activation since I believe my example was a linux VM.