Unfortunately, one of the most annoying SSIS bugs did not make the cut for the SQL Server 2005 SP2 bug fix list [1]: namely, when you add additional output columns to a Derived Column Transformation (and maybe other kinds as well) that is upstream from one or more Union All Transformations, the new columns you add get "stuck" behind the Union All transformations--that is, they do not show up as input columns in the Union All, and consequently do not flow past the Union All. Generally, for me anyway, this comes up when you edit an upstream Derived Column Transformation that already has one or more Union All Transformations downstream from it.

The best way I have found to fix this is to delete and re-add each and every Union All Transformation that is downstream from the place where you added the new column(s). Alternately, you can edit each Union All and manually add the missing columns, but since this usually happens to me with multiple columns, I don't prefer this solution most of the time.

Has anyone else found a way to prevent and/or fix this pesky bug? Or have I mis-characterized the problem?

Dan