Consider the following scenario:
You schedule a Microsoft Lync meeting in Lync Room System. Then, the scheduled meeting appears in the calendar of Lync Room System.
You select the "join meeting" tile on the table-top touch meeting console, or on the front-of-room touch displays.
You hear the sound that indicates that Lync Room System is connecting to the meeting.
In this scenario, if you try to join the meeting from another Lync endpoint, the Lync endpoint shows that Lync Room System has joined the meeting. However, Lync Room System is still stuck on the screen that displays the "joining conference room to meeting" message.
To resolve this issue, install the following update:
2962967 Update 2962967 for Lync Room System: June 2014