I first ran across this problem when adding a virtual adapter to a VMware virtual machine, but it’s also an issue for physical adapters in a multi-homed system or one with multiple network adapters. When you add an adapter to a system that uses the NetBEUI protocol — such as Windows 2000 Professional — you might see the message “ERROR: A duplicate name exists on the network when you start the system.” Or, if you add the NetBEUI protocol to a multi-homed system, you’ll probably see the message after you restart the computer.
The error is generated because Windows 2000 can support NetBEUI on only one network interface. NetBEUI uses the computer’s name to identify the network node and the names must be unique on the network segment. Having NetBEUI on two adapters causes a conflict because each interface tries to represent itself with the same name.
The solution is to remove the NetBEUI protocol from one of the adapters. Go to Start | Settings | Network And Dial-Up Connections. Right-click the interface from which you want to remove NetBEUI and choose Properties. Deselect NetBEUI Protocol in the components list and then click OK.