If you restrict the SQL username to 'dbo' that will exclude any other users - where the username is actually populated. But if SQl user is null it gets included in the trace whatever you do. Probably best is to capture the trace to a table (see SQl profiler help), then you can search the results via a SQL statement. Beware though - command text may be truncated, and many values are stored as int rather than readable strings - so you have to look in MSDN to translate the values.