Windows Deployment Services generates duplicate client computer names when the %MAC variable is used
In the Active Directory domain network, you try to use Windows Deployment Services (WDS) to deploy a version of the Windows NT operating system. To make the client computer name that is automatically generated unique in the network, you configure a new computer naming policy for WDS. When you configure the new policy, you use the variable %MAC to include the network adapter media access control (MAC) address of the client computer as part of the computer name.
However, when WDS deploys the client computers during the unattended phase, the computer names that are generated for the client computers show zeros instead of the MAC addresses of the client computers. Therefore, the process fails because of duplicate computer names in the network.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB957051.