This article applies as of PRTG 20


How can I resolve issues where PRTG fails to update or install a remote probe due to an existing Npcap library on my system?

Updating or installing PRTG while Npcap is running

When you have Npcap 0.995 or later running at the time you want to update or install PRTG, there may be issues with the update or installation process.


Update or installation stops showing a Windows error message

The update or installation process may stop when trying to install Npcap. Windows stops and shows the error message

A LWF & WFP driver installation tool has stopped working. A problem caused the program to stop working correctly. Please close the program.

Closing the program does not solve the issue. PRTG does not start again and the update or installation process was not successful.


Troubleshooting solution

Unfortunately, this is a known issue with Npcap. If you experience this issue, you need to manually stop npcapoem.exe via the Windows Task Manager, for example, to continue and finish the PRTG update or installation process.

Note: When you use the auto-update function of PRTG, you do not get an error message. PRTG just does not start again. In this case, you need to manually stop npcapoem.exe as well.


Windows Server 2008 R2: Auto-update is unsuccessful

On Windows Server 2008 R2, a Windows Security dialog appears when trying to install Npcap, asking you if you trust the software you want to install. The content is as follows:

Would you like to install this device software?
Name: Nmap Project Network Service
Publisher: Insecure.Com LLC

You need to manually click Install to continue the update or installation process.

If you use the auto-update function of PRTG, you do not see this dialog. You also do not get an error message. PRTG may just not start again and the update or installation process may not be successful.

Another issue may be that Packet Sniffer sensors and Packet Sniffer (Custom) sensors show a Down status or an Unknown status with the message that the file winpcap.dll is missing.


Troubleshooting solution

Unfortunately, this is a known issue with Npcap. If you experience this issue, you need to manually update or install PRTG and confirm the Windows Security dialog. For this, click Install.

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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.