After you install Windows NT 4.0 Service Pack 4 (SP4), you cannot connect to a downlevel server or share using a fully qualified domain name (FQDN) that is longer than 32 characters. The NET USE command does not work and the following error message is displayed:
system error 67: The network name cannot be foundThis behavior occurs when you connect to a downlevel server and the server message block (SMB) dialect negotiated is LAN Manager 2.1 (dialect number 6).
This problem occurs because there are several changes to the redirector in SP4.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.