The IMAP service crashes intermittently on Exchange 2007, and Event ID 5000 is logged

On a Microsoft Exchange Server 2007 server, you may find that the IMAP service crashes intermittently. When this problem occurs, IMAP clients cannot access their mailboxes. Additionally, the following error message is logged in the event log:

Event Type: Error
Event Source: .NET Runtime 2.0 Error Reporting
Event Category: None
Event ID: 5000
Description: EventType clr20r3, P1 microsoft.exchange.imap4.exe, P2 8.1.278.2, P3 481f7feb, P4 microsoft.exchange.imap4, P5 8.0.0.0, P6 481f7feb, P7 a6, P8 17, P9 system.nullreferenceexception, P10 NIL.

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

To resolve this problem, download Update Rollup 4 for Exchange 2007 Service Pack 1. Then, install Update Rollup 4 on the Exchange server. For more information about Update Rollup 4 for Exchange 2007 Service Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:

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