Consider the following scenario:
You clear the Enable file upload option in Persistent Chat category.
You set EnableP2PFileTransfer to True in Conferencing Policy Settings.
You upload a file to a persistent chat room in Microsoft Lync 2013 (Microsoft Skype for Business).
In this scenario, you receive the following error message:
Problem Event Name: APPCRASH
Application Name: lync.exe
Application Version: XX.X.XXXX.XXXX
Application Timestamp: 53c5caa5
Fault Module Name: Uc.dll
Fault Module Version: XX.X.XXXX.XXXX
Fault Module Timestamp: 53c5df18
Exception Code: c0000005
Exception Offset: 0000000000231bdd
OS Version: X.X.XXXX.X.X.X.XXX.X
Locale ID: 2057
To fix this issue, install the September 8, security 2015 update (KB3085500) for Lync 2013 (Skype for Business).
Note Lync 2013 was upgraded to Skype for Business in April 2015.