Does Exchange Server 5.5 include a feature that I can use to run a pop-up script that presents a warning message about viruses every time someone logs on to Microsoft Outlook?
Your question is thought provoking. After all, most virus outbreaks occur because users double-click on attachments that they shouldn't be fooling with. Reminding them repeatedly certainly can't hurt and might even help. Unfortunately, Exchange doesn't include a direct way to send such a message. You could use Windows NT logon scripts to display a warning when the user logs on to the workstation. An enterprising developer could write a DLL that wraps the Messaging API (MAPI) logon functions and displays the message. However, no preconfigured method exists for accomplishing your goal.