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How can I disable the installation of Npcap before updating or installing PRTG?



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The installation of Npcap can cause several issues when I try to update or install PRTG, especially on a system where a different application or service also uses packet inspection. Is it possible to disable the installation of Npcap so that a PRTG update or installation process runs smoothly and other services are not affected?

npcap packet-sniffing prtg update

Created on Apr 24, 2020 5:34:58 AM by  Maike Guba [Paessler Support]

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This article applies as of PRTG 20

How to disable the installation of Npcap before updating or installing PRTG

As described in PRTG update process is unsuccessful while trying to install Npcap. What can I do?, there might be issues with the Npcap installation during an update of PRTG, causing the PRTG update or installation process to stop.

There might also be issues with existing Packet Sniffer and Packet Sniffer (Custom) sensors because of a missing winpcap.dll file. This missing .dll file can also cause further issues if the file is used in a different productive service that is running on the same probe system.

For this reason, we provide a registry key option as of PRTG 20.2.59 to disable the installation of Npcap.

Steps to take

Note: It is important that you back up your system before manipulating the Windows registry!

Take the following steps on each probe system where you want to disable the installation of Npcap before updating or installing PRTG.

  1. Open the registry editor and navigate to the following keys:
    • On a 64-bit Windows system, go to
      HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Paessler\PRTG Network Monitor\Probe\PreventNpcapInstall
    • On a 32-bit Windows system, go to
      HKEY_LOCAL_MACHINE\SOFTWARE\Paessler\PRTG Network Monitor\Probe\PreventNpcapInstall
  2. This step only applies if the DWORD value PreventNpcapInstall does not exist.
    Create a new DWORD value: In the current path, right-click and select New | DWORD Value. Name the new DWORD value PreventNpcapInstall.
  3. Change the value of PreventNpcapInstall: Right-click PreventNpcapInstall and select Modify. In the value field, enter 1. Confirm with Ok. This disables the installation of Npcap.
    To enable the installation of Npcap again, set the value of PreventNpcapInstall to 0.
  4. Restart the probe system.

Note: If you disable the installation of Npcap, you cannot use existing or set up new Packet Sniffer or Packet Sniffer (Custom) sensors anymore.


Created on Apr 24, 2020 5:41:41 AM by  Maike Guba [Paessler Support]

Last change on Jan 7, 2021 9:23:39 AM by  Maike Guba [Paessler Support]



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Thanks for adding this feature, this has been causing us some pain, we had to disable auto-updates as all our remote probes failed to update due to this issue.

Here's a command line version to add the key to prevent npcap. Change the 1 to 0 to disable and remove Wow6432Node for 32 bit. REG ADD HKLM\SOFTWARE\Wow6432Node\Paessler\PRTG Network Monitor\Probe /v PreventNpcapInstall /t REG_DWORD /d 1

Created on Jun 2, 2020 1:47:43 PM by  Tim Boothby (80) 2

Last change on Jun 3, 2020 6:53:42 AM by  Tim Boothby (80) 2

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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.