After upgrading the DLP platform to version. 16.0 RU1, Network Monitors have a problem where Packet Capture fails to start.
You can open a command prompt and attempt to run Program Files\Symantec\DataLossPrevention\DetectionServer\16.0.10000\Protect\bin\packetcapture.exe and see the following pop up error messages,
PacketCapture.exe - System Error
Release : 16.0.1
You must uninstall npcap and re-install npcap version 1.1.