I have a user who has Outlook 2003 SP3 installed. The problem emails come with an "Untitled Attachment" which her Outlook cannot open. Even right-click and save as produces no access to the attachment. What is in the the attachments are mutiple files - pdf's usually and usually the text of the previous forwards. Other people CC'd on the email get the untiltled attachment but CAN open it.
If she forwards it to another user in her same Exchange 5.5 based organization or my external Exchange 2003-based system other people can open the email attachment and view/save the attached files. What's more if you forward that email back to the problem user she CAN open it in her Outlook 2003 SP3 client.
So far I have tried to uninstall and reinstall MS Office 2003 and have tested that with the base version - not SP3 - still fails to open attachments. I have also tried deleting the domain users profile and re-creating it with no luck. Setting up the affected user's Outlook profile on another domain PC will get the attachment to open so it must be something local to her PC and not a problem with her Exchange 5.5 mailbox.
When you can open the attachment on another user's PC, it show a blank email To, From and Subject and the message is called HTML message. It will have the body of the original email.