We recently encountered a issue during our internal tests.  Visual Studio 2008 failed to create any Biztalk 2009 projects.  We had not made any changes to the dev server and were not sure what caused this problem.  Initial investigations showed some automatic updates had been applied on the server. 

When you try to create a new Biztalk project using

File -> New Project -> Any BizTalk Project Type

You get the error message: Creating project ‘project name’… project creation failed.

We could get the project system to work by repair installing Biztalk but that doesn’t seem like a solution.  Further debugging revealed that the following registry setting was modified by a VS update.

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\VisualStudio\9.0\Projects\{FAE04EC0-301F-11d3-BF4B-00C04F79EFBC}]

"PossibleProjectExtensions"="csproj"   - Original VS install reg value. "PossibleProjectExtensions"="csproj;btproj" - Post Biztalk installation reg value

The following is the entry for the 64 bit version of VS:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\VisualStudio\9.0\Projects\{FAE04EC0-301F-11d3-BF4B-00C04F79EFBC}

Biztalk installation modifies the reg value to register its project extension with the C# project factory.

A repair of VS (something that is done as part of patch installation) is going to restore it to its original state. That's the standard MSI repair behavior.

If one modifies the reg value to what BizTalk installer is doing, the project creation succeeds.

I don’t see a simple way way of patching anything on Biztalk side, we are trying to work with the VS team to see if there is a way to preserve the setting during patch updates on VS.  For now the simplest fix is to modify the registry entry.   Will keep you updated if we find a better solution on this.

-Guru