Before migrating servers to Windows Server 2003, determine whether your Windows NT4 server hardware and Windows NT4 server-based applications are compatible with the Windows Server 2003 family operating system.
Use the Microsoft Compatibility Check Tool available on the Windows Server 2003 installation CD-ROM to test application compatibility.
Before you begin an inplace upgrade of a domain, it is a good practice to force synchronize the primary domain controller and backup domain controllers.
Seriously consider performing an inplace upgrade from Windows NT4 to Windows 2003 instead of building a brand-new forest and moving objects to minimize the time, effort, cost, and user interruption involved in a clean forest migration process.
Review the server event and system logs upon completing any upgrade.
Review the Active Directory Users and Computers snap-in to ensure that all security principles have been migrated successfully to Window Server 2003 and Active Directory.
Before migrating BDCs, review the backup domain controller and member server's application and system logs to identify issues that can affect the progress of your migration.
When configuring the Active Directory database locations, ensure that your server hardware configuration plan takes recoverability and performance into account.
For best performance, install the Active Directory databases on a separate hard disk than the server operating system and server page file.
For best recoverability, use disk fault tolerance such as RAID or disk mirroring for the Active Directory databases.
If you are experiencing problems creating a trust, raise the forest functional levels using the Properties page of the Active Directory domain.
Install the ADMT utility on a domain controller located in the target domain when possible.
Test any (ADMT) migration before performing an actual migration of user accounts.
