I have a C# application that connects to a named SQL Express instance on the local machine using OleDBConnection:

_connection = new OleDbConnection(_strConn);
_connection.Open();

_strConn is something like this: "Provider=sqloledb;Data Source=.\NAMEDINSTANCE;Initial Catalog=dbname;User Id=sa;Password=password;"

If I debug the application, the connection works fine. If I run the application from Windows Explorer (the same debug compilation), I get an "OleDBException: Login timeout expired" in the Open() line after 30 seconds. The strange thing is the exception happens even if I attach the debugger to the exe. I can see that the connection string is correct and everything seems fine. I can't fine any extra information in the SQL Express error log or SQL Activity Monitor either.

If it helps, here is the exception:

    System.Data.OleDb.OleDbException: Login timeout expired
   at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)
   at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.OleDb.OleDbConnection.Open()

I imagine that find the issue with the information I give here might be difficult, but I don't know where else to look or what other tests to do, so any ideas on what it could be or what test I could do to find out will be really appreciated.