HOTFIX: Some e-mail messages remain in the queue on an Exchange 2003 server

This is of interest to my alter-ego

“Some e-mail messages remain in the queue on a server that is running Microsoft Exchange Server 2003. Additionally, the message sender receives non-delivery report (NDR) 4.4.7 messages that indicate the delivery failures.

This problem does not occur [recur?] if you restart the Microsoft Exchange Information Store service on the Exchange 2003 server.

This problem occurs because the Microsoft Exchange Information Store service populates an internal property cache with incorrect e-mail message header data. When this problem occurs, the cache in the Microsoft Exchange Information Store service reaches the maximum limit of 65,536 entries. When the cache is fully populated, more entries cannot be added. This behavior causes an error condition in which some messages cannot be sent.

To reset the cache, restart the Microsoft Exchange Information Store service.“

Source: http://support.microsoft.com/default.aspx/kb/941060