DOCUMENT:Q238189  08-MAY-2002  [exchange]
TITLE   :XCON: Duplicate Messages Delivered After MTA Restart
PRODUCT :Microsoft Exchange
PROD/VER:winnt:5.5 SP2
OPER/SYS:
KEYWORDS:exc55sp2

======================================================================
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The information in this article applies to:

 - Microsoft Exchange Server, version 5.5 SP2 
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SYMPTOMS
========

When the message transfer agent (MTA) is under heavy stress, Db*.dat files are
sometimes not cleaned up properly. In some cases, these files are also not
marked as "used." When the MTA is restarted, the queues are rebuilt based on all
of the Db*.dat files that are "not used" in the Mtadata folder. Because these
files have not been cleaned up or marked as delivered, restarting the MTA in
this state produces duplicate mail to the local store.

In addition, when the MTA is in this state it cannot be shut down cleanly.
Consequently, either killing the MTA or hard-booting the server are the only
options to bring it down.

CAUSE
=====

Viewing the Performance Monitor counter MSExchangeMTA, with the instance Work
Queue Length, reveals a steady increase but no message backlog in any other
queue. This is a result of the Db*.dat files not being marked as "used."

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem. This fix may receive additional
testing at a later time, to further ensure product quality. Therefore, if you
are not severely affected by this problem, Microsoft recommends that you wait
for the next Microsoft Exchange Server version 5.5 service pack that contains
this fix.

To resolve this problem immediately, contact Microsoft Product Support Services
to obtain the fix. For a complete list of Microsoft Product Support Services
phone numbers and information about support costs, please go to the following
address on the World Wide Web:

   http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.

The English version of this fix should have the following file attributes or
later:

Component: Message Transfer Agent

+---------------------------+
| File name    | Version    | 
+---------------------------+
| Dbserver.sch | N/A        | 
+---------------------------+
| Dcprods.cat  | N/A        | 
+---------------------------+
| Ems_rid.dll  | 5.5.2621.0 | 
+---------------------------+
| Emsmta.exe   | 5.5.2621.0 | 
+---------------------------+
| Info4log.cfg | N/A        | 
+---------------------------+
| Infoblog.cfg | N/A        | 
+---------------------------+
| Infodlog.cfg | N/A        | 
+---------------------------+
| Infollog.cfg | N/A        | 
+---------------------------+
| Infoplog.cfg | N/A        | 
+---------------------------+
| Infotlog.cfg | N/A        | 
+---------------------------+
| Mtacheck.exe | 5.5.2621.0 | 
+---------------------------+
| Mtamsg.dll   | 5.5.2621.0 | 
+---------------------------+
| P2.xv2       | N/A        | 
+---------------------------+
| X400om.dll   | 5.5.2621.0 | 
+---------------------------+
| X400omv1.dll | 5.5.2621.0 | 
+---------------------------+



STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Exchange Server
version 5.5.

Additional query words:

======================================================================
Keywords          : exc55sp2 
Technology        : kbExchangeSearch kbZNotKeyword2 kbExchange550SP2
Version           : winnt:5.5 SP2
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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