After you upgrade to Microsoft Office 2003 by using a custom transform (.mst) file that contains an Office Profile Settings (.ops) file, the Mail icon is missing from Control Panel.
This issue may occur if the registry entry that points to the Mlcfg32.cpl Control Panel file is missing or damaged.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To resolve this issue, follow these steps:
Make sure that the following Control Panel file exists and that it works as expected: