You can assign a MAC address manually if you need to ensure that the same MAC address is always assigned to the virtual network adaptor for a virtual machine.
Assign a MAC address manually instead of allowing Fusion to assign it to be sure that the following situations occur:
When a physical machine is converted to a virtual machine, the MAC address of the network adapter is changed. For software in which the licensing is linked to the MAC address, this can be a problem. Manually assigning the correct MAC address is the solution.
Shut down or power off the virtual machine. You cannot change the setting while the virtual machine is powered on or suspended.