Doug-
I suspect that what you are suggesting is what actually happened. I copied the entire directory from machine to machine with a zip disk so I know the two tables were identical and did not contain any duplicate records. I had not run the SDT from the tools menu in some time. Thank you - I would not have thought of that explanation. In any case, I cannot duplicate the situation now.
A problem is a problem only as long as it has a possible solution. Lacking that, it becomes a FACT!