Hi,

If you have any issue with the Classic Outlook 2010 Plug in, including installation or doesn’t display in Outlook 2010.

Ensure you have MSXML 4.0 Service Pack 2 installed on your computer

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=19662

Choose your language

Download the first Link :

MSXML.msi                        (5.0 MB)

Thanks