[updated 29/9/12 with new link] Given the recent comments about AD validation I thought I would share this excellent document on verifying your AD before you begin a migration (or at any other time) Active Directory Health Check - Active Directory This document outlines a basic procedure for validating the health of your domain and is a good practice for iterative maintenance and an excellent pre-check before doing any potentially dangerous domain operations I would add a couple of extra tests to the list in this document, which would be placed after the 1st DCDIAG test, also perform: DCDIAG /test:DNS /DNSALL /e /v DCDIAG /test:DcPromo /e /v DCDIAG /test:RegisterInDNS If you system passes these tests then it is a good indication of health. ttfn David Technorati Tags: SBS 2003 , Windows Server 2008 , Active Directory , migration , Microsoft , SBSC , Partners