NIC Teaming (aka NIC bonding, network adapter teaming, Load balancing and failover, etc.) is the ability to operate multiple NICs as a single interface from the perspective of the system. If that team member is ever removed from the team and attempt standalone operation with that MAC then there could be duplicate MAC address on the network assuming the vNIC is also in operation.Ī solution commonly employed to solve the network availability and performance challenges is NIC Teaming. This shouldn’t cause an issue as long as the team member that has the same MAC as the vNIC remains in the team. That has the same MAC address as one of the NIC (physical NIC) members of the NIC team. What the event is saying is that you have a host vNIC (virtual NIC presented to the host that is connected to the Virtual Switch) This is showing up as a Warning in the event log. If you are using Windows Server 2012 R2 and configured NIC Teaming you could have this Event ID : 16945
