Exchanage System Manager mailbox sizes do not reclaim after archive

Problem:
Exchanage System Manager mailbox sizes do not reclaim after user archived their mails in Outlook, although mailbox sizes were shown to be reduced in the Outlook client.

Solution:

Apply the following as described in http://support.microsoft.com/kb/895265/en-us :

Follow these steps for each Exchange 2003 database on each Exchange 2003 computer that is missing the Background Cleanup registry entry or the Track Duplicates registry entry:

1. Click Start, click Run, type regedit, and then press ENTER.
2. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\\Private-MailboxStoreGUID

3. Create the following registry entry:

Registry entry name: Background Cleanup
Value type: REG_ DWORD
Value data: 60000 (decimal) or 0xEA60 (hexadecimal)

4. Create the following registry entry:

Registry entry name: Track Duplicates
Value type: REG_ DWORD
Value data: 1

5. Quit Registry Editor.
6. Perform one of the following tasks:
* Dismount and then remount each one of the affected information store databases.
* Restart the Microsoft Exchange Information Store service.