The importance attribute of a message is lost when an Exchange 2007 user accesses a high-importance message or a low-importance message from Exchange Server 2007 by using a non-Outlook POP3 client or IMAP4 client

When a Microsoft Exchange 2007 user accesses a high-importance or low-importance message from Exchange Server 2007 by using a non-Outlook POP3 client or IMAP4 client, such as Outlook Express or Windows Mail, the importance attribute is lost. Therefore, the message is recognized as a normal message. However, in Microsoft Office Outlook or in Outlook Web Access (OWA), the importance attribute is presented as High or Low.

Importance is a registered header as defined in RFC 4021. Many different headers other than the "Importance" header can be used to represent the end-to-end importance of an e-mail message. Some of these are the "X-Priority" (1-5) header or the "X-MSMail-Priority" (High, Low, and Normal) header. However, Exchange Server 2007 currently provides only the "Importance" header for outbound MIME messages (POP/IMAP). Therefore, if the client does not recognize the "Importance" header, and you expect to use the "X-Priority" field or the "X-MSMail-Priority" field to determine if the message is important, the problem occurs.

To resolve this problem, install Update Rollup 8 for Exchange 2007 Service Pack 1.
For more information about Update Rollup 8 for Exchange Server 2007 Service Pack 1, see the following Exchange Help topic: For more information about how to obtain the latest Exchange service pack or update rollup, see the following Exchange Help topic:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about RFC 4021, visit the following Web site: