I have also run into this problem, and after searching for about 3 weeks I gave up and rebuilt the server. My problem was something to do with DNS that wouldn't allow DC's to be added. I had uninstalled and reinstalled DNS, tried numerous things off the KB and still got the same errors! You can backup exchange and restore it to a different box, I didn't backup the system state incase I transferred the problem. I had to manually created the AD users and then restore the Exchange backup. 6 months later and no ill effects so far! ...Spence :) -----Original Message----- From: Calderón Vilches Luis Daniel [mailto:Daniel@xxxxxxxxxxxx] Sent: 12 February 2004 19:54 To: [ExchangeList] Subject: [exchangelist] FW: Disaster Recovery Exchange 2K with Win2K AD http://www.MSExchange.org/ Hi, Me again... Maybe I didn't explain myself very well, so let me put it in other words. How can I reinstall a Exch2K server that is also the only Domain Controller of the domain? Remember that the reason for the reinstallation is a corrupted Active Directory that does not allow to add additional domain controllers. TIA, Daniel