Skype for Business 2015 (Lync 2013) becomes unresponsive when you join a meeting with many participants

Applies to: Skype for Business 2015Lync 2013


When you join a Skype meeting that involves many participants by using Microsoft Skype for Business 2015 (Lync 2013) on Windows, the client becomes unresponsive for a period.


To fix this issue, install the June 4, 2019, update (KB4464593) for Microsoft Skype for Business 2015 (Lync 2013).
  • Before you apply this update, make sure that you create a GPO to add the following new DWORD registry keys and set the values under the path:
DWORD EnableLargeMeetingProcessing 1
DWORD LargeMeetingMinimumRosterCount = 20 (default)
DWORD LargeMeetingRosterLoadingDelayInSec 30 (default)
  • Lync 2013 was upgraded to Skype for Business in April 2015.