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.
