FIX: Connection Failure Errors Occur After Upgrade to MSDE 2.0

After you upgrade to Microsoft Data Engine (MSDE) 2000 on a computer that is running Microsoft Windows NT, Microsoft Windows 2000 or Microsoft XP, the following error message may occur with client applications that attempt to connect to MSDE:

The SQL Server Authentication mode has been changed to the Windows Authentication default.

To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

To work around this problem, use either of these methods:

• Update the SQL Server Authentication mode back to SQL Server Authentification by using the information in the following Microsoft Knowledge Base Article:
  285097  (http://support.microsoft.com/kb/285097/EN-US/ ) INF: How to change the default login authentication mode to SQL
• After you upgrade to MSDE 2000, use the REGSVR32 command to unregister the ATL.dll file, and then re-register ATL.dll.

Microsoft has confirmed that this is a problem in Microsoft SQL Server Data Engine 2000. This problem was first corrected in Microsoft SQL Server 2000 Service Pack 2.NOTE: The specific fix for this bug is in the Microsoft SQL Server Data Engine 2000 component of SQL Server 2000 Service Pack 2.

This problem only occurs under the following conditions:

• MSDE 1.0 Service Pack 2, or later, was installed before the upgrade.
• The computer that is being upgraded is running Windows NT 4.0, Windows 2000 or Windows XP.
• MSDE 2000 is installed by using Windows Installer (Msiexec.exe).
• After the upgrade to MSDE 2000, an ATL based DLL component is registered on the computer.
• The upgrade to MSDE 2000 requested use of the SQL Server Authentication mode (switch SECURITYMODE=SQL).

When the preceding conditions are true, and the ATL based DLL is registered, Windows Installer discovers that the Comnevnt.dll file is not installed properly. When the Windows Installer discovers that the Comnevnt.dll file is not installed properly it runs the MSDE 2000 setup again in maintenance mode, which resets the SQL Server Security mode.