When Lync is not signed in, the Groups collection is empty. Upon signing in, Lync Server provisions the client with all of the local user's groups. When each individual group is provisioned, this event occurs. If Lync is already signed in when your application starts up, this event does not occur. This is because Lync Server has already provisioned Lync with all of the local user's groups. When the local user creates a new group, Lync Server provisions the client with the created group and the event is Occurs for the newly created group.