• I'm not sure if this applies or not, but I had the same issue with SQL 2008 on a 6 node (5 active, one passive) cluster.

    http://blogs.msdn.com/b/psssql/archive/2010/07/09/why-is-my-sql-clustered-instance-changing-authentication-modes.aspx

    Michael L John
    If you assassinate a DBA, would you pull a trigger?
    To properly post on a forum:
    http://www.sqlservercentral.com/articles/61537/