I just posted the problem with the same title. This is a correction to that post.j What I originally created was a contact list, with about 100 contacts. Then I selected about 80 of them and created a distribution list with about 80 of the original 100. It is the original contact list that had some duplications (only 8 or 9), then suffered two stages of deletions. Further, I was never able to find the distribution list in the contact list. Perhaps this is related to the problems.