Greetings! I am currently running Win2K/AD domain with compatible mode. I managed to run the vampie procedure to migrate all credentials (SIDs and passwords) to Samba/PDC with OpenLDAP backend. The existing XP clients logon to the under the Samb/PDC domain without re-join the domain because they expect to locate the domain in Win2K/AD way. Here is the Event View message from NetLOGON The domainof this computer, AB has been downgraded from Windows 2000 or newer to Windows NT4 or older. This computer cannot funtion prpoerly in this case for authetication purposes. This computer needs to rejoin the domain. The following error occurred: There are currently no logon servers available to service the logon request. logon server is avaialbe (the same Samba/PDC) because a new XP client can join and logon to the domain with no problem. The question is how to twist the registry parameter(s) so the existing XP clients will look for a NT4 or orlder style domain? According to MS Q314861. NT4 uses discovery to find its domain ... .... Any information and suggestion are appreciated. Please response to ksun@abinitio.com -- Kang Sun