You may experience the following issues in Microsoft Skype for Business 2016:
After you set the EnableTracing parameter to False by using the Set-CsClientPolicy cmdlet for Skype for Business 2016, the .ETL and MediaStack tracing still continues.
Assume that you set the EnableTracing registry key to 0 under the HKEY_CURRENT_USER\Software\Microsoft\Tracing\WPPMediaPerApp\Skype\ETW path. After you restart the Skype for Business 2016 client, the registry dwords change to a value of 1, and WPPMedia tracing still continues.
After you set the Logging in Skype for Business option to Off under Help your support team help you in General settings, tracing still continues after you restart the application.
To fix this issue, install the May 7, 2019, update (KB4464532) for Microsoft Skype for Business 2016.