This issue occurs when you select the RTCSrv.exe process under the Overview tab in the Resource Monitor tool in Microsoft Lync Server 2013.
When this issue occurs, the process stops running. Additionally, the event id 1000 is logged in the Application Log:
This issue occurs because a deleted object is referenced to use when the process is selected.
To resolve this issue, install the July 2015 cumulative update 5.0.8308.920 for Lync Server 2013 (Front End Server and Edge Server).