I use <a href=”http://www.virtualbox.org/>Virtualbox</a> regularly. Recently I wanted to use a VDI twice for different machines. One intended for the dev and the other for a live system.
Simple copying of the VDI file doesn’t work since the UUID is still the same, but it’s quite easy to change it if you know how…
VBoxManage internalcommands setvdiuuid disk.vdi
That’s it and it works flawlessly.