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I have issues with additional services after updating to PRTG 19.2.50. What can I do?



I upgraded my PRTG installation to version 19.2.50. Now, I have issues with DHCP on any server where I installed a remote probe. Also, there are random DNS server and DFS server issues. What can I do about it?

additional-services dhcp npcap-loopback-adapter prtg troubleshooting

Created on Jul 5, 2019 8:44:00 AM by  Maike Guba [Paessler Support] (2,404) 2 1

Last change on Jun 27, 2022 12:53:36 PM by  Brandy Greger [Paessler Support]

1 Reply

Accepted Answer



This article applies as of PRTG 19.2.50

The Npcap loopback adapter and additional services

As of PRTG 19.2.50, Packet Sniffer and Packet Sniffer (Custom) sensors use the Npcap library instead of the deprecated WinPcap library to monitor your traffic. With version 19.2.50, PRTG also installs a loopback adapter as part of this Npcap library. If the remote probe system also runs additional services, for example, a DHCP server, this adapter might result in unexpected behavior.

Possible errors because of an installed Npcap loopback adapter

The following errors might occur because of an installed Npcap loopback adapter:

Tips for troubleshooting

To solve these issues, you need to manually uninstall the Npcap loopback adapter:

  1. Right-click the Windows start button and select Device Manager.
  2. Click the > arrow next to Network adapters to open a list of currently installed network adapters.
  3. Right-click Npcap Loopback Adapter and select Uninstall device.
  4. Click Uninstall to start the uninstall process.

Note: With PRTG 19.x.51, the Npcap loopback adapter is not automatically installed anymore. If you directly upgrade to this version without upgrading to PRTG 19.x.50 first, PRTG does not install the Npcap loopback adapter.


Created on Jul 5, 2019 9:27:47 AM by  Maike Guba [Paessler Support] (2,404) 2 1

Last change on Jan 5, 2023 8:13:56 AM by  Brandy Greger [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.