Problem upgrading from Vista to Windows 7 if you have .NET Framework 4 beta 1 installed

Description of the issue

There is an issue with the .NET Framework 4 beta 1 and Visual Studio 2010 beta 1 that can cause problems if you do the following:

  1. Install Windows Vista
  2. Install the .NET Framework 4 beta 1 (or Visual Studio 2010 beta 1 because it will install the .NET Framework 4 beta 1 behind the scenes)
  3. Upgrade your OS to Windows 7

When doing this, some programs that depend on the .NET Framework will not work correctly after you finish your OS upgrade.  Once a system is in this state, there is not a way to repair it other than to re-install Windows 7.

This issue will be fixed in the .NET Framework 4 beta 2, but will affect systems that have .NET Framework 4 beta 1 installed prior to the OS upgrade.

How to work around the issue

To work around this issue, you must do the following in the exact order listed below:

  1. Uninstall VS 2010 beta 1 if it is installed on your system
  2. Uninstall .NET Framework 4 beta 1
  3. Uninstall Visual C++ 2010 beta 1 redistributable if it is installed on your system
  4. Reboot
  5. Upgrade your OS from Windows Vista to Windows 7

You can find more specific steps that describe how to uninstall all of the above beta 1 products in this post on Aaron Ruckman’s blog.