Upgrading a 2000 server from member status to domain controller status in Brazil. Dcpromo working well at replication stage all seemed well. About 3 hrs later, noticed that users having issues with name resolution, checking DNS in a 16 dc child domain I noticed that the child domain forward lookup zone was disappearing on 12 of the dc. During the investigation, the other 4 dc lost this zone as well, had to recreate the zone from a secondary zone server.
All dc were set to Active Directory Primary Integrated status, pulling from a master server at the forest level not sure why or how these could be overwritten or allow the forward zone to be removed. Opened call with Microsoft, they are slow on the response so looking for other ideas. We are in process of upgrading all DC from 2000 to 2003 with 13 at 2003 (fsmo role holders complete) and 5 left at 2000.