The IMAP4 service crashes intermittently, and Event ID 4999 is logged in Exchange Server 2007

On a Microsoft Exchange Server 2007 server, after you set the value of the CalendarItemRetrievalOption parameter to Custom for the IMAP4 service, you may find that the IMAP4 service crashes intermittently. When this problem occurs, all IMAP clients cannot access their mailboxes. Additionally, the following error message is logged in the event log:

Event Type: Error
Event Source: MSExchange Common
Event Category: General
Event ID: 4999
Description: Watson report about to be sent to dw20.exe for process id: <process id>, with parameters: E12, c-buddy-RTL-AMD64, <version>, M.E.Imap4, M.E.D.Storage, M.E.D.S.ImapItemConverter.GetHeaders, System.NullReferenceException, <version>. ErrorReportingEnabled: False

To resolve this problem, install Update Rollup 7 for Exchange 2007 Service Pack 1. For more information about Update Rollup 7 for Exchange Server 2007 Service Pack 1, see the following Exchange Help topic: For more information about how to install the latest Exchange service pack or update rollup, see the following Exchange Help topic:

To set the CalendarItemRetrievalOption parameter to Custom for the IMAP4 service, run the following command in Exchange Management Shell:For more information about the Set-IMAPSettings command, visit the following Web site:

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