Error, this module is blocked from loading into Local Security Authority Bonjour/mdnsNSP.dll

Hello,

I had a customer having this problem, here some fix ;

My customer installed DymoLabel V8, wich installed Bonjour. The version installed by the sofwtare was Bonjour 2.0.2.0, wich is really old, and therefore had a 2010 dll. Other app may install other version, but i think we are at version 3.0.0.0 ( or higher ) for the software.

The software is used for iTunes indeed, but it automatically discover printers, scanners, airplay devices ect. There is also another part of that software that is Bonjour mDNS, and is the core part of the software, and is the one who might bring problem.

In the end, old software might need Bonjour service or not, but the service that is activated by it is a security risk, particullary on public or untrusted network.

open services.msc, search for Service Bonjour, disable it.

Another way is with regedit, nagivate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\Parameters\Protocol_Catalog9, search for the dll and remove it.

There is no official way to autorise it, but stopping or even uninstalling the service should do it.

I have the exact same thing, except only at startup.

I downloaded Process Explorer from Microsoft, and ran it. It says it is being used by Adobe Creative Cloud, which I have installed to use Lightroom and Photoshop. It also says about 5 copies of it are currently running, so I don't know why this specific one won't load. But anyhow... lol

Hope that's helpful.

I think obs complains about having to install latest net (8.0) sdk, which might install the bonjour, for no reason, obs does not use it or need it. but obs uses net on windows.

edit: never mind, handbrake uses net and complains, not obs. obs does something different with bonjour.

running OBS (Open Broadcaster Software) seems to also trigger this same issue/warning.

I second that. Running a previously stable system. Installed OBS Studio on 5/2, and have been getting the error ever since. Just tried the winget upgrade, so we'll see if that fixes things.

My name is Jonathan Deives. I'm an Independent Advisor and I will be happy to help you.

This pop-up usually appears because of the iTunes app. Do you have it installed?

If so, temporarily uninstall it to see if the problem persists.

running OBS (Open Broadcaster Software) seems to also trigger this same issue/warning.