If you have an XNA Game Studio 3.1 project that includes an XACT audio project and plan to upgrade it to XNA Game Studio 4.0, there is an additional manual step you must take to upgrade your XACT project to the newer XACT file format required by XNA Game Studio 4.0.

We updated the XACT tools used by XNA Game Studio 4.0 at the last-minute due to an issue that we discovered shortly before shipping.  Unfortunately, we did not have time to add information about how to upgrade XACT projects to the XNA Game Studio 4.0 upgrade documentation.  Hopefully this blog post will help folks who run into this issue figure out how to upgrade their XACT projects so they will work correctly with XNA Game Studio 4.0.

Description of the issue

If you have an existing XNA Game Studio 3.1 project that uses an XACT audio project, then you upgrade your project to XNA Game Studio 4.0, you will see an error like the following in the Visual Studio error list when you attempt to compile it with XNA Game Studio 4.0:

The .xap file was created with a version of XACT that is incompatible with the XNA Framework Content Pipeline version used by this project. Refer to the documentation for options to resolve this mismatch.

How to update an XACT project from XNA Game Studio 3.1 to the format required by XNA Game Studio 4.0

Here are some more specific steps you can use to upgrade an XACT project used in XNA Game Studio 3.1 to the version of XACT required by XNA Game Studio 4.0:

1. Make a backup copy of your .xap file if you would like to keep a copy of the .xap file from before upgrading it with the XACT tool.
2. On a system with XNA Game Studio 4.0 installed, click on the Start menu, choose All Programs, then Microsoft XNA Game Studio 4.0 | Tools | Microsoft Cross-Platform Audio Creation Tool 3 (XACT3).
3. In the Microsoft Cross-Platform Audio Creation Tool 3 (XACT3) tool, open the .xap file from the project that you upgraded from XNA Game Studio 3.1 to XNA Game Studio 4.0.  When it loads, you should see the following message in the XACT UI:
   
   ---------------------------
   XACT Version Mismatch
   ---------------------------
   This project file was created with the March 2009 release of XACT. You are running the February 2010 release.
   If you save this project, it will be saved as the current version and may no longer work with the version of
   XACT it was originally created with.
   ---------------------------
   OK  
   ---------------------------
   
   
4. Click OK to upgrade the .xap project to the new February 2010 format.
5. Save the .xap project in the XACT UI and close the XACT UI.
6. Go back to Visual Studio 2010, open the project that you upgraded from XNA Game Studio 3.1 to 4.0 and choose to build it again.

Additional notes about this error message

The steps above explain how to upgrade an XACT project created with XNA Game Studio 3.1 to an XACT project that can be used with XNA Game Studio 4.0.  However, there are a few different scenarios where the “.xap file was created with a version of XACT that is incompatible with the XNA Framework Content Pipeline version used by this project” error message can occur, so the above workaround may not successfully resolve this error in all cases.

Here are some of the possible configurations where this error will occur:

• Attempting to compile an XNA Game Studio 4.0 project that was upgraded from XNA Game Studio 3.0 or 3.1 that includes an XACT project
  
  This is the scenario that the workaround above applies to
  
  
• Attempting to compile an XNA Game Studio 3.1 project that includes an XACT2 project
  
  This is similar to the scenario that the workaround above applies to.  You can find more details about this scenario in this blog post.
  
  
• Attempting to compile an XNA Game Studio 3.0 or 3.1 project that includes an XACT project created with the version of XACT that ships with XNA Game Studio 4.0
  
  This is the inverse of the above scenario. You need to create a new version of your XACT project using one of the XACT tools included with XNA Game Studio 3.1 at the following location on the start menu:  All Programs | Microsoft XNA Game Studio 3.1 | Tools.  You should use Microsoft Cross-Platform Audio Creation Tool 2 (XACT2) for XNA Game Studio 3.0 projects and Microsoft Cross-Platform Audio Creation Tool 3 (XACT3) for XNA Game Studio 3.1 projects.
  
  
• Attempting to compile an XNA Game Studio 4.0 project that includes an XACT project created with a version of the XACT tool other than the one that ships with XNA Game Studio 4.0 (for example, the version of XACT in the DirectX SDK)
  
  This is similar to both of the above scenarios.  You need to make sure the XACT project is saved in the format of the version of XACT that ships with the version of XNA Game Studio that you are using.