Symptoms
Assume that you installĀ June 7, 2016, update for Lync 2013 (Skype for Business). Then, you join a meeting without audio devices. In this situation, a blank window is displayed. The expected scenario is that you receive a messageĀ that indicates that you can't join the meeting because of no audio device.
Resolution
To fix this issue, install MS16-097: Description of the security update for Lync 2013 (Skype for Business): August 9, 2016 (KB3115431).
Note Lync 2013 was upgraded to Skype for Business in April 2015.