Login failed for user ''. The user is not associated with a trusted SQL Server connection.

Problem:

SQL Server error message Login failed for user ''. The user is not associated with a trusted SQL Server connection. when trying to connect to database using SQL Server Authentication.

Solution:

1. Start > Programs > Microsoft SQL Server 2005 > SQL Server Management Studio
2. Right-click the Server name, select Properties > Security
3. Under Server Authentication, select SQL Server and Windows Authentication Mode
4. The server must be stopped and re-started for this change to take effect