MAC address options when creating a full clone

I am planning to create a full clone of a Windows machine on the same drive as the existing VM. There is a slight possibility I will run both VMs at the same time.

I have read the explanations about the MAC address options in Chapters 1.13 and 8.39, but I am stumped as to which to choose.

Section 1.13 states that the “Generate New MAC Addresses For All Network Adapters value” in GUI dialog “is the default setting,” while Chapter 8.39 states that “the default behavior is to reinitialize the MAC addresses of each virtual network card.” Although these may be the same, my sense is that I want the latter but I don’t have sufficient experience or knowledge to resolve this.

I would appreciate a reference that sheds more light on this issue and any advice.

Just to clarify, the chapters are from the VirtualBox manual (

Each documentation is saying the same thing in different words… Re-initializing is the same as generating new MAC addresses.

To help you understand what’s happening, no matter whether you clone or not all machines must be uniquely identified on the same network, and the two things that identify a machine are its network identification (MAC address) and network name (Hostname). Machines fundamentally identify themselves uniquely by its MAC address but humans have a hard time reading random collections of octet numbers and the MAC address isn’t routable, so an IP address is then assigned to that MAC address mainly for humans to read and enable routing. The other thing that has to be unique is its name on the network that resolves to the IP address and nowadays the hostname naming system is widely considered the default because it’s also the system used on the Internet.

The documentation says that it’s also common to deploy a cloned machine on the same network as the original network, so the cloning operation automatically and by default creates a new MAC address for the cloned machine, and I haven’t checked Virtualbox, but a new hostname should be generated too (If not, you’ll have to manually change that).

Virtualbox isn’t unique in this of course.
You’ll find the same thing in all other virtualization as well.


Thank you for your detailed comments.

After considering both the VM VirtualBox Manager dialog and command line options, I decided to use the former, selecting the Generate New MAC Addresses option and accepting all of the defaults. The clone generated successfully.

Thanks again.