Exchange2003 is running in co-existence with Exchange5.5. A few mailboxes were moved. By default the POP service is disabled, it was enabled and started. Nothing else was done with regards to setting up a Virtual Pop server etc. Outlook express was used to check email for one user. The account settings in outlook express was set to point to the exchange2003 address. It connected well, but brought down the emails of another user. The settings in outlook express was ok. Any ideas why this happened?