Consider the following scenario:
You deploy Enhanced 9-1-1 (E9-1-1) in a Microsoft Lync Server 2010 environment.
You configure a notification URI to receive IM notifications when emergency calls are made.
You assign the location policy for E9-1-1 to a Lync 2010 user.
The user makes an emergency call.
In this scenario, no IM notification is sent to the notification URI.
This issue occurs because the location information from the client contains special XML characters. Therefore, the server cannot handle the XML message that is sent by the Lync 2010 client.
To resolve this issue, install the following cumulative update:
2514982 Description of the cumulative update package for Lync 2010: November 2011