BizTalk Compilation problem – Compiler for file type ‘*.xsd’ failed. Value cannot be null. Parameter name: pUnk error

I’ve got the following error while I wanted to compile a BizTalk Server Project:

“Error 2
Build failed. Compiler for file type ‘*.xsd’ failed. Value cannot be null. Parameter name: pUnk“

The error occurs if there is any *.xsd file added to the project.


I don’t know what caused the problem but I did a repair on the BizTalk installation and the problem was gone.


  • Click Start, click Run, type Appwiz.cpl and then click OK.
  • In the list of currently installed programs, click Microsoft BizTalk Server 2006 (or 2004), and then click Change/Remove.
  • In the BizTalk Server 2004 Installation Wizard window, click Repair and then click Next.
  • After the BizTalk Server Installation Wizard repairs BizTalk Server, click Finish to close the BizTalk Server Installation Wizard window.
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.

4 thoughts on “BizTalk Compilation problem – Compiler for file type ‘*.xsd’ failed. Value cannot be null. Parameter name: pUnk error”

  1. Hi,

    I’m getting the same error. I have re-installed the BizTalk 2006 R2 Developer Tools and SDK on my build server. But this didn’t correct the problem. Any other hints which could help ?

      1. In fact, i just installed the Developer tools and SDK for building projects on my BUILD machine. Do you think it’s necessary to install the whole BizTalk package even on the BUILD machine ?

  2. Without BizTalk + VS on the development computer you hardly could do anything helpful to develop BizTalk project.
    I never try you scenario, but I found this discussion:

    My suggestion is that you create a full LAB environment in your machine (personal is not my favorite) or in a Virtual PC – I like this last option, because it allows me to have different platforms (2006, 2009 or 2010)

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