http://sqlblog.com/blogs/alberto_ferrari/archive/2006/07/31/data-flow-components-constructors-and-ssis.aspxYesterday I had to fix a simple still subtle bug in TableDifference , I think sharing the experience will be useful for everybody involved in custom component creation. The component has some fields that are initialized in the component constructor, atenCommunityServer 2.1 SP2 (Build: 61129.1)