Consider the following scenario:
You have four Microsoft Lync users (user A, user B, user C and user D). User A and user B are enabled for the remote call control feature (RCC).
User A makes a call to user B from an IP telephone that uses Lync 2013 user interface.
User B transfers the call to user C by using Lync 2013.
User C accepts the call. Then, user A and user C are in a conversation.
User C ends the call.
In this scenario, user A cannot close the call window. Additionally, the following message and the Resume Call button are displayed in the window.
This call is on hold.If user A tries to make a new call to user D, the call window between user A and user C will be in the background and the call to user D will fail.
This issue occurs because the call ID between user A and user B is not cleared in Lync 2013.
To resolve this issue, install the following update:
2880474 Description of the Lync 2013 update: April 2014