You cannot install the Microsoft Compressed (LZH) Folder add-in on a computer that is running Windows 7.
The Compressed (LZH) Folder add-in can be installed only on certain earlier Japanese Windows operating systems. By default, Japanese versions of Windows 7 include the Compressed (LZH) Folder functionality. Therefore, the installation of this add-in is blocked in Windows 7.
This behavior is by design.
In a Japanese version of Windows 7, use the built-in feature to work with LZH archives.
Article ID: 971613 - Last Review: Oct 5, 2009 - Revision: 1