An account name conflict occurs when you upgrade a Windows NT 4.0 primary domain controller to a Windows 2000 domain controller (313357)

SYMPTOMS

When you upgrade a Microsoft Windows NT 4.0-based primary domain controller to Windows 2000, naming conflicts may occur when you upgrade the domain. The conflicting user names are named $AccountNameConflictN, where N is a sequential number that starts from 0. When this issue occurs, you see the following entry in the System event log:

Event Type: Warning
Event Source: SAM
Event Category: None
Event ID: 16384
Date: 11/16/2001
Time: 3:45:02 AM
User: N/A
Computer: DC01
Description:
The account Name could not be upgraded since there is an account with an equivalent name.

CAUSE

This issue occurs because several user, computer, and trust relationship names that are used in earlier versions of Windows are restricted in Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

266633 "Computer Name Is Already in Use" Error Message When You Add User Names in Windows 2000

This issue may also affect user names that contain umlauts. Security Accounts Manager (SAM) account names that contain umlaut characters in Windows NT 4.0-based domains may conflict with similar accounts when you upgrade the domain because of the way in which Windows 2000 depicts these characters.

RESOLUTION

Before you upgrade a Windows NT 4.0-based domain to Windows 2000, scan your user names for possible conflicting names. Rename any conflicting accounts before you upgrade the domain, or note the conflicting names and modify them after the upgrade.

MORE INFORMATION

Windows NT 4.0 allows umlauts in user names. For example, the names Otto (without the umlaut) and Oetto (with the umlaut) do not conflict. However, Windows 2000 handles the umlauts as standard characters. Therefore, Otto and Oetto would be the same name. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

273633 USERNAME Environment Variable May Differ from Actual User Name

If you upgrade a Windows NT 4.0-based primary domain controller in a domain that contains both names (Otto and Oetto), the Otto account remains a valid user name, but the Oetto account is renamed to $AccountNameConflict0 (if it is the first conflicting name). The following entry is recorded:

Event Type: Warning
Event Source: SAM
Event Category: None
Event ID: 16384
Date: 11/16/2001
Time: 3:45:02 AM
User: N/A
Computer: DC01
Description:
The account oetto could not be upgraded since there is an account with an equivalent name.