During Veeam replication jobs, your vCenter triggers the VM MAC conflict alarm. This happens because when a VM replica is created, it has the same MAC address and UUID as the original VM. This situation is totally expected because a newly created replica is an absolute copy of the original VM with exactly the same properties. This doesn’t create any issue, since the replicated virtual machine is not powered on, but more importantly because vCenter changes both replica’s MAC address and UUID. So, the issue is gone after a few moments, but the alarm remains in the console and it may be annoying. So, here’s how you can suppress the alarm.
Virtual To The Core
Virtualization blog, the italian way.