If you are finding the below errors within your event log on your Exchange 2003 server, it is due to missing registry files.

Error 1
Event ID: 1240, The expected registry value “Track Duplicates” under registry key “SYSTEM\CurrentControlSet\Services\MsExchangels\server\
Private-djj63126-0940-45f2-94f2-123456789f1″ could not be found. Some server operations may be affected.

Error 2
Event ID: 1240, The expected registry value “Background Cleanup” under registry key “SYSTEM\CurrentControlSet\Services\MsExchangels\server\Public-123d45d-67f0-8afc-9a2d-dc105b1fae2d” could not be found. Some server operations may be affected.

Notes: Always ensure you have a full backup before implementing changes

If you have installed Exchange Service Pack 1, the problem was corrected in Exchange Service Pack 2. Or an alternative way is to apply a hotfix which you can request by clicking here (Important: Read through the notes before installing)

If you already have Exchange 2003 Service Pack 2 install, follow the instructions below to recreate the keys.

1) Click Start
2) Click Run
3) Type regedit and press enter
4) Locate and click the following registry subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\<ServerName>\
Private-<MailboxStoreGUID> (If you have more then one Private key folder, click here for instructions on how to locate the correct one)

5) Create the following registry entry:

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

6) Create the following registry entry:

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

7) Exit from registry editor.
8.) Dismount and then remount each one of the affected information store databases or restart the Microsoft Exchange Information Store service