If your clients use POP3 to retrieve mail from an Exchange 2000 or Exchange 2003 server, you may receive an error message that's similar to the following:
Event ID: 1023
Event Source: POP3SVC
Event Type: Error
Event Category: Content Engine
Error 0x7d6 occurred while rendering message 0001-0000007d063a
for download for user firstname.lastname@example.org.
A configuration problem on the client's computer is the cause of this error message. Outlook clients configured with both the Internet E-mail and Microsoft Exchange Server services in their profile generate such errors.
The client computer pulls mail down using POP3. If the Exchange service attempts to access a message that the user has already deleted via POP3, the server generates the 1023 error message.
While this error isn't harmful, 1023 events can fill the application log quickly, making troubleshooting other problems more difficult.
To get rid of 1023 errors, configure the Outlook client to use only one service in the profile. If a user needs both services, configure a separate profile for each service. Once the client uses only one service per profile, the annoying 1023 error messages will go away.