Developing Pipelines Components – UNC Path Error

Recently I developed a custom pipeline component, this component as a specified characteristic: it used a third-party DLL (provided by the client).

After successful compilation, the ALL assemblies must be put on “C:\Program Files\Microsoft BizTalk Server 2006\Pipeline Components” folder (Alternative: put component DLL in pipeline Components folder and the third-party DLL in GAC)

But, while adding the component in the VS toolbox, I was surprised with the following error:

“You have selected an invalid pipeline component assembly. Please check security settings for the assembly if you are loading it from an UNC path.”

You have selected an invalid pipeline component assembly - UNC path


  • First, check that your pipeline component class is public.
  • Also, make sure any assemblies you reference from the custom pipeline component are in the GAC or Pipeline Components folder (if that’s where you drop your custom pipeline component assembly).
  • Check for missing dependencies, they all have to be put on GAC or Pipeline Components folder

In my case, the DLL that I try to used (that was provided by the client), I success build the solution (without error or warning) in Visual Studio, but when I checked the DLL have some dependencies that weren’t installed in GAC (in my case nunit.framework.dll version

I install dependencies in GAC and solved the problem.

Author: Sandro Pereira

Sandro Pereira lives in Portugal and works as a consultant at DevScope. In the past years, he has been working on implementing Integration scenarios both on-premises and cloud for various clients, each with different scenarios from a technical point of view, size, and criticality, using Microsoft Azure, Microsoft BizTalk Server and different technologies like AS2, EDI, RosettaNet, SAP, TIBCO etc. He is a regular blogger, international speaker, and technical reviewer of several BizTalk books all focused on Integration. He is also the author of the book “BizTalk Mapping Patterns & Best Practices”. He has been awarded MVP since 2011 for his contributions to the integration community.

5 thoughts on “Developing Pipelines Components – UNC Path Error”

  1. if you have changed the name space of the class and you haven’t updated it with resource manager, which would be usually the first line of code , if you are using the pipeline component wizard, – this will also show you the same error

  2. Nice post Sandro. This is currently killing me slowly, and painfully. I’ve checked for public class, dependencies and base name passed to resource manager but still no luck. Did anyone ever discover any way to get a more descriptive error message?

    1. Check whether ‘description’ method of ‘IBaseComponent’ has been changed to return some string value.Try update the default

      “get { throw new NotImplementedException(); }” into
      get { return “Your description”; }

  3. Move your custom pipeline component *.dll to folder C:Program Files (x86)Microsoft BizTalk Server 2010Pipeline Components

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