Domain Migration Administrator 7.x
Migrating from Active Directory to Active Directory
Error: 'Logon Failure: The target account name is incorrect'.
Logon failure error occurs when users in the source domain try to access a migrated server.
Computer name is duplicated elsewhere in the domain or forest.
After you migrate a computer from an AD domain to an AD domain, the computer account is referenced in both directories. To resolve this issue, delete the computer account from the source AD domain. You may also need to reboot the computer that you are trying to connect from.
This issue is addressed in Microsoft Knowledge Base article 244210.