Duplicate Messages Via POP from Outlook Express This document explains how to resolve a known issue where an Outlook Express POP client downloads duplicate messages. The issue occurs when the "leave a copy on the server" option is selected and subsequently the Outlook Express message store becomes corrupted. There are two ways to resolve this problem, both of which require changes to the client PC: Either: Upgrade the client PC to Internet Explorer to version 6 with Service Pack 1 Or: - open the message store folder in the client PC (the default location is C:\WINDOWS\Application Data\Identities\) - rename any files that begin with "POP3" - reboot the computer - open Outlook Express, no messages will be visible. Click Send/Receive, all messages will be downloaded, and the client should no longer receive duplicate messages.