XCON: MTA Stopping with Event ID 2143: Unrecoverable Error

• Microsoft Exchange Server, version 4.0

SYMPTOMS

The Microsoft Exchange message transfer agent (MTA) terminates unexpectedly with an event similar to the following (as viewed in the Application Event Log):

   Event ID: 2143
   Source:MSExchangeMTA
   Type:Error
   Category:Internal Processing
   Description:
   A fatal MTA database server error was encountered. Call Microsoft
   Product Support.
   Unrecoverable error: ODXOINIU - Object does not exist. About to
   terminate. Called from MTA. Procedure 205. Object ID: 06000072.
   Attribute ID: 55. Attribute value number: 1. Referenced object: 00000000
   (00000000 => N/A). Referenced object error 0. [1 DB Server XFER-IN 22
   101] (16)

   Event ID: 2186
   Source:MSExchangeMTA
   Type:Warning
   Category:Internal Processing
   Description:
   An MTA database server error was encountered while locking an object.
   Called from MTA. Procedure 100. Database error code: ODXOINIU - Object
   does not exist.
   Object at fault: 06000072. [DB Server XFER-IN 22 59] (14)

CAUSE

When an MTA object is created, its reference count is initialized to one. When the object is passed to an entity that can delete the object, the reference count must first be incremented. When an object deletion is requested, the reference count is decremented (and when the reference count for the object reaches zero, the object is physically deleted).

There is a race condition in the MTA, where a newly initialized object (reference count of one) is passed to an entity (the Microsoft Exchange Internet Mail Connector) before the reference count is incremented. An object deletion is requested by the Internet Mail Connector (IMC) (which decrements the reference count to zero, and causes the object to be deleted). When the MTA attempts to access the object, the object had already been deleted and an "ODXOINIU - Object does not exist" complaint is raised by the MTA.

STATUS

The Microsoft MTA has been modified to ensure that the reference count for the object is incremented prior to being passed to an entity that could delete it.

Microsoft has confirmed this to be a problem in Microsoft Exchange version 4.0. This problem was corrected in the latest Microsoft Exchange 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K