Scenario: You are logged into a computer running Windows Server 2008/ Windows Vista/7 and SQL Server as a member of the administrators group and you cannot use Windows Authentication mode for connecting to the database using SQL Server Managment Studio.Server Furthermore upon examining the SQL Server logs you see the following:
EventID: 18456
Login failed for user MYDOMAIN\MYLOGIN'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: <local machine>]
Workaround: Connect using the "sa" account. or Run SQL Server Management Studio "As Administrator" (right-click "run as Adminsitrator"
See the following:
http://msdn.microsoft.com/en-us/library/aa905868.aspx
See the following Blogs for more information:
Also see :
http://blogs.msdn.com/b/sql_protocols/archive/2006/02/21/536201.aspx