Server 2003 is reaching the end of support, and it’s quite possible that decommissioning any legacy Domain Controllers running this OS is an important project on your list.We’ve already covered some of the most common scenarios that involve Server 2003:
– Active Directory upgrade
– File Server Migration
– DHCP migration (including Failover configuration)

In this screencast, we demonstrate how to demote the last Server 2003 Domain Controller in the forest. While this might seem quite a straightforward process – just run DCPROMO and then raise the Domain/Forest functional level – it is typical for a demo network where everything is perfect and simple.
In our screencast, we start with AD health check, go through some of the most common problems and omitted steps – like configuring the time service on the new PDC emulator, and finish with restarting the KBRTG service on all DC to avoid Kerberos authentication issues.

For your convenience, we provide the text file with our project plan and the commands that we are using in the screencast here .

Step 1 In the first step, we perform AD Health Check and clean up Sites & Services and the AD integrated DNS zone.

Step 2 Next, we move all FSMO roles to a Server 2012 DC, reconfigure the time service, and demote the last Server 2003 Domain Controller. Finally, we raise the Domain and Forest functional level.