Consider the following scenario:
On a website that hosts a Silverlight application for Microsoft Lync 2010, the default page of the website starts the Silverlight application.
You add the website to the trusted sites zone in Internet Explorer.
You open the default page by using a Uniform Resource Location (URL) address that does not contain the page name. For example:
In this scenario, the Silverlight application does not start. However, when you open the default page by using a URL address that contains the page name, the Silverlight application starts successfully. For example:
This issue occurs because of a bug in an internal method of the Lync 2010 Client API. This method checks the trust level of a given URL incorrectly and ignores a URL address that does not contain a page name.
To resolve this issue, install the following cumulative update:
2467763 Description of the cumulative update package for Lync 2010: January 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.