Dear all, I have got previously a server running SBS 2003 and configured as a DC that gets client W7 laptop joinned to the domaine without any trouble. ON that server I reformat it all and Install a fresh Server 2008 R2 as a DC. From my client machine, I can reach the domaine by pinging it of by its name without trouble. I can see it as well when runing nslookup, the Ip adress of the DC is return Then when trying to joing the domain I am prompt to a login. Then I enter the administrator account of the DC and password that I am absolutly sure of that. Trouble is that I get error all the time "Logon Failure, unknown username or password" 2 days that I am fighting with this. Any help? regards sergeYour knowledge is enhanced by that of others.

Please verify your user name and password. http://support.microsoft.com/kb/279212/en This posting is provided "AS IS" with no warranties or guarantees , and confers no rights. Microsoft Student Partner Microsoft Certified Professional Microsoft Certified Systems Administrator: Security Microsoft Certified Systems Engineer: Security Microsoft Certified Technology Specialist: Windows Server 2008 Active Directory, Configuration Microsoft Certified Technology Specialist: Windows Server 2008 Network Infrastructure, Configuration

in what format do you enter username? did you try yourdomain\yourdomainadminaccount or do you just enter the account name?

i try both When trying to join a client computer to a domain, does the client computer need to be create frst in AD as well as the client user or does those operation gets done by joining the domain ? Your knowledge is enhanced by that of others.

i try both When trying to join a client computer to a domain, does the client computer need to be create frst in AD as well as the client user or does those operation gets done by joining the domain ? Hello, there is no need for this. The computer account will be created in the domain during the join process. According to the error you use a wrong password or the user account is written wrong. Please post an unedited ipconfig /all from the DC/DNS and the problem machine.Best regards Meinolf Weber Disclaimer: This posting is provided "AS IS" with no warranties or guarantees , and confers no rights.

Hi, Thanks for posting here. In addition , have you also tried resetting password for this domain administrator account on windows server 2008 R2 domain controller and try rejoin with new password again to see if this issue persist Or maybe you can also try creating a new account and joining it as a member of domain administrators group then join computers with this account . Troubleshooting Domain Join Error Messages http://social.technet.microsoft.com/wiki/contents/articles/troubleshooting-domain-join-error-messages.aspx Thanks. Tiger LiPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.