This policy setting allows you to prevent a dialog box from being shown when the Windows Desktop Search 4.0 or above system ...

This policy setting allows you to prevent a dialog box from being shown when the Windows Desktop Search 4.0 or above system component is not present on the user's computer and removes the other links provided in Outlook to allow users to download the component. The new search functionality in Outlook requires Windows Desktop Search 4.0 or above.If you enable this policy setting, the dialog box is not shown.If you disable or do not configure this policy setting, the dialog box is shown when this system component is not present.  Users are prompted with a dialog box when Outlook starts that explains how to download the system component to install on their computers. In addition, other links are provided by default in Outlook to allow users to download the system component. Note: If the required Windows system component is not available, the buttons in the Outlook Search ribbon tab will be disabled regardless of how this policy setting is configured.