I understand what you are saying, but this problem occurs when *any* subscriber posts to the list, not just one. From what my subscribers are reporting, this happens with every post to the list. I first checked to be sure the list was not subscribed to itself. I also considered a subscriber might have a forward setup that was sending list posts back to the list address. But that would only explain one such incident, like your misconfigured header idea, and not how this happens with every post, from every subscriber. The log entries I previously copied to this list were made by different subscribers. I have a copy of the logs from that entire day, and with every post, the duplicate error message was sent out. So, what the subscribers are reporting is, in fact, occuring. Any ideas? ----- Original Message ----- From: "F. J. Kelley" <[log in to unmask]> look at the "Received:" headers. One of your subscribers mailers is misconfigured and is reposting to the list. you will need to look these headers over very carefully (start at the bottom), but the key is when you see your listserver address(es) the second time (ie the mail leaves the listserver then shows up back at the listserver as if it were a new post).