When a client issues a QUIT command to end a POP3 session, the MSExchangePOP3 service crashes occasionally on a Microsoft Exchange Server 2007 Client Access server. Additionally, the following event is logged in the Application log:
Log Name: Application Source: Application Error Date: Date Event ID: 1000 Task Category: (100) Level: Error Keywords: Classic User: N/A Computer: Computer Description: Faulting application name: Microsoft.Exchange.Pop3.exe, version: version, time stamp: time stamp Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000 Exception code: 0xc0000005 Fault offset: offset Faulting process id: process id Faulting application start time: start time Faulting application path: C:\Program Files\Microsoft\Exchange Server\ClientAccess\PopImap\Microsoft.Exchange.Pop3.exe Faulting module path: unknown Report Id: report id
This issue occurs because of a NullReferenceException exception when the Exchange server processes a POP3 session quit command. The NullReferenceException exception is caused by a race condition during the POP3 session object disposal. In this race condition, the VirtualServer object is set to NULL before it is used. Therefore, the MSExchangePOP3 service crashes.
To resolve this issue, install the following update rollup:
2655203 Description of Update Rollup 7 for Exchange Server 2007 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the QUIT command, visit the following Microsoft website: