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Upgrading to Wireshark 3.4.3 64-bit Npcap 1.10 failing

asked 2021-01-29 22:40:30 +0000

GaryR gravatar image

Npcap 1.10 Setup is failing Could not load: C:\Users\UserName\Appdata\Local\Temp\nstC359.tmp\SimpleSC.dll I confirmed that SimpleSC.dll exists.

I get the same error when I try to fall back to Wireshark 3.4.2 64-bit.

What do I need to do to recover?

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Similar to npcap issue 226
Have you tried doing the install outside of Wireshark using the npcap installer ?

Chuckc gravatar imageChuckc ( 2021-01-29 23:17:17 +0000 )edit

I did remove npcap and attempted to use the npcap installer. I got the same results, unfortunately.

GaryR gravatar imageGaryR ( 2021-01-30 01:45:47 +0000 )edit

C:\Users\UserName\ - are you logged in as "UserName"?
Is there a chance the TEMP environment variable is hosed?

C:\Users\IEUser>set | findstr /I temp
Chuckc gravatar imageChuckc ( 2021-01-30 02:48:51 +0000 )edit

I am logged in as UserName.

H:>set | findstr /I temp




GaryR gravatar imageGaryR ( 2021-01-30 15:16:24 +0000 )edit

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answered 2021-02-01 11:48:54 +0000

André gravatar image

This is probably because access to the executable code (dll) in your temp directory is blocked by the OS or AV.

The Npcap driver seems to be installed correctly before the "runtime error 255" error is shown. If you kill the npcap-installer task (cancel button remains grey), the Wireshark installer will continue and end normally.

When starting the Wireshark installer you can also deselect the npcap update, avoiding this issue.

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I have removed the Npcap driver. Wireshark 3.4.3 is running, which I did not expect. I thought Wireshark needed Npcap. What is the Npcap driver needed for? Thanks.

GaryR gravatar imageGaryR ( 2021-02-02 14:42:43 +0000 )edit

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Asked: 2021-01-29 22:40:30 +0000

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Last updated: Feb 01 '21