VBoxManage list hdds
You must get UUID of virtual drive you want to clone. As an egzamples lets assume that UUID is 973b3243-8168-41c3-bb29-1c9865eaec7c. Having this, one executes clonevdi command as follows:
VBoxManage clonevdi 973b3243-8168-41c3-bb29-1c9865eaec7c outfilename.vdiI noticed that when coping VDI to new Vbox, networking does not work good.
I managed to repair this by restarting it (my guest is Linux):
Also sometimes this failed, because the command was restarting wrong network interface, e.g. eth4 instead of eth2. This can be change in /etc/network/interfaces