Consider the following scenario:
You install the March 8, 2016, update for Lync 2013 (Skype for Business) (KB3114831).
You create a new Skype meeting in Microsoft Outlook 2013.
You add attendees and select a room for this meeting.
You try to select presenters by using the Meeting Options button in the new created Skype meeting.
In this situation, no attendees or presenters is presented in the Meeting Options Presenters dialog box.
To fix this issue, install the July 5, 2016, update (KB3115261) for Lync 2013 (Skype for Business).
Note Lync 2013 was upgraded to Skype for Business in April 2015.