Upgrading a Windows 2000 Active Directory (AD) schema before installing Windows Server 2003 Release 2 (R2) domain controllers (DCs) proved a little tricky. The upgrade procedure calls for running the Adprep utility, once in the forest on the forest schema master DC (Adprep /forestprep) and again on each Win2K domain infrastructure master (Adprep /domainprep).
Having previously upgraded a Windows Server 2003 R1 server, I used the same procedure. I first ran the command
from Windows Server 2003 R2 CDROM 1. The procedure ran OK. Because this was a single DC environment, I didn't have to wait for replication to occur. I then ran the command
on the same DC. Again, this was a single DC environment, so the Flexible Single-Master Operation (FSMO) roles of schema master and infrastructure master were both on the same DC.
The next step is running the Dcpromo tool on the new DC. This procedure includes choosing whether to install a new domain or install an additional DC in the same domain. I chose the latter and finished the installation. After running for a little while, the execution stopped and I received the error message, The version of the Active Directory schema of the source forest is not compatible with the version of Active Directory on this computer.
This wasn't good. I reran both utilities, and they both reported to have been run before. I then started searching for a way to verify that the changes in AD had actually occurred. I found the Microsoft article "Operations that are performed by the Adprep.exe utility when you add a Windows Server 2003 domain controller to a Windows 2000 domain or forest" (http://support.microsoft.com/kb/309628), which details the changes made by both procedures.
Further research led me to an online discussion about the same error I experienced. It turns out that the Adprep utility on CD-ROM 1 of Windows Server 2003 R2 isn't the latest release. It will bring AD up to version 30, whereas the R2 version of AD is 31.
Fortunately, the solution to this problem is simple. There's a newer version of the Adprep utility on Windows Server 2003 R2 CD-ROM 2 that you can use. After I ran the newer version, the adprep.exe /forestprep procedure reported a successful upgrade from version 30 to 31. Just to make sure, I also ran adprep. exe /domainprep, but it reported no changes necessary. After the upgrade to version 31, the Dcpromo tool ran just fine.