Messages that have duplicate message IDs are deleted when they are archived to an Exchange 2007 mailbox

You archive e-mail messages to a Microsoft Exchange Server 2007 mailbox from an external system or by using Exchange Server 2003 Standard Journaling. In these scenarios, e-mail messages that contain the same message ID are discarded, and only the oldest copy of each e-mail message remains in the mailbox.

This issue occurs because Exchange 2007 uses the Duplicate Detection function during the archiving of e-mail messages. In some cases, the original e-mail message may have been split into multiple copies, each with the same message ID. When Exchange 2007 receives these messages for archiving into a single mailbox, messages that have the same message ID as a previously received message are discarded.

For more information about Message Journaling in Exchange 2007, see the following TechNet articles:

For Exchange Server 2007

To resolve this issue, download and install Update Rollup 2 for Exchange 2007 Service Pack 2.

Prerequisites

The following list contains prerequisites for the update rollup:

• You must have Exchange 2007 Service Pack 2 installed to install this update rollup. For more information about how to obtain the latest Exchange Server 2007 service pack, click the following article number to view the article in the Microsoft Knowledge Base:
  937052 How to obtain the latest service pack or update rollup for Exchange 2007

For more information about Update Rollup 2, click the following article number to view the article in the Microsoft Knowledge Base:

For Exchange Server 2003

For more information about how to resolve this issue for Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:

After you install the update rollup, you must make changes to the registry on the server that is running Exchange 2007.

Two registry subkeys control the Duplication Detection function in Exchange 2007. The subkeys are ParametersPrivate and ParametersPublic.

• The ParametersPrivate subkey is used to disable duplicate detection for mailboxes.
• The ParametersPublic subkey is used to disable duplicate detection for public folders.

For each of these subkeys, create the Disable All Duplicate Detection registry entry. When you set this entry to 1, you disable duplicate detection for mailboxes or public folders. To do this, follow these steps.

Important Disabling duplicate detection on a Mailbox server enables any message to be delivered to a recipient with a duplicate message ID. We recommend that you make this change only on Mailbox servers that contain Journal mailboxes and no other mailboxes.

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/MSExchangeIS/ParametersPrivate
   
   If the ParametersPrivate registry subkey does not exist, follow these steps:
   1. On the Edit menu, point to New, and then click Key.
   2. Type ParametersPrivate, and then press ENTER.
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type Disable All Duplicate Detection, and then press ENTER.
5. On the Edit menu, click Modify.
6. Type 1, and then click OK.
7. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/MSExchangeIS/ParametersPublic
   
   If the ParametersPublic registry subkey does not exist, follow these steps:
   1. On the Edit menu, point to New, and then click Key.
   2. Type ParametersPublic, and then press ENTER.
9. On the Edit menu, point to New, and then click DWORD Value.
10. Type Disable All Duplicate Detection, and then press ENTER.
11. On the Edit menu, click Modify.
12. Type 1, and then click OK.
13. Exit Registry Editor.