Topic Last Modified: 2009-02-09
The Microsoft Exchange Server Best Practices Analyzer reads the following registry subkey to determine whether the Track Duplicates registry entry is present:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\<ServerName>\Private-<MailboxStoreGUID>\Track Duplicates
If the Best Practices Analyzer finds that the Track Duplicates entry is missing, the tool generates an error message.
If the Track Duplicates registry entry is missing, you may experience one or more of the following symptoms in the Exchange organization:
- Exchange System Manager does not display mailbox sizes
correctly. In this scenario, the mailbox size that appears in
Exchange System Manager differs from the mailbox size that appears
in Microsoft Office Outlook. Also, when you remove mailbox items,
the mailbox size may not decrease as expected. In this scenario,
Exchange 2003 does not reclaim the space that the deleted mailbox
items used.
- When you try to move mailboxes, the operation is unsuccessful,
and the following event is logged in the Application log:
Event Type: Error
Event Source: MSExchangeIS Mailbox Store
Event Category: General
Event ID: 1205
User: N/A
Computer: <ServerName>
Description: Failed to create the mailbox of /o=<organizationName>/ou=<organizationalUnit>/cn=Recipients/cn=<username> with error 0x4e3.
- Exchange 2003 may not generate unread receipt messages for
items that are deleted before they are read.
To address this issue, re-create the Track Duplicates registry entry.
 Important: |
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| This topic contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe. |
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Click Start, click Run, type regedit, and then press ENTER.
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Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\<ServerName>\Private-<MailboxStoreGUID>
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Create the following registry entry:
Value name: Track Duplicates
Value type: REG_ DWORD
Value data: 1
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Exit Registry Editor.
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Dismount and then remount the affected information store databases. Alternatively, you can restart the Microsoft Exchange Information Store service.
For More Information
For more information, see Microsoft Knowledge Base article 895265, Mailbox or folder sizes are incorrect in Exchange System Manager, Move Mailbox operations are unsuccessful, and unread receipt messages are not delivered in Exchange Server 2003.