If you're upgrading to the newly released GAX February 2008 from GAX July 2007 installed on top of VS2008 beta/rtm you are required to uninstall the later and all installed guidance packages. The following are the instructions you should follow to do so:

1) Un-register and Un-install all existing guidance packages:

a. Un-register all previously registered guidance packages from within Visual Studio: open every guidance package solution, right click on the guidance package project node and select “Unregister� Note that you can’t un-register a guidance package if you have already deleted its source code.

b. Un-install all guidance packages installed from MSIs: you could either run the original MSI used to install the guidance package or try to install it from Add/Remove Programs. Please make sure there are no open instances of Visual Studio before performing this step. If a MSI fails to uninstall you will need to resort to MSI Cleanup[1] to get it removed.

2) At this point you should try to un-install GAX from Add/Remove Programs. If this fails you will need to run GaxTroubleshooter[2] using the /RemoveGax switch which will remove GAX from your system. You can then use MSI Cleanup to remove the GAX entry from the Add/Remove Programs.

Note that if you had GAX July 2007 on top of VS2005, the above instructions doesn't apply to you, you are not required to uninstall neither GAX nor any guidance package. You can run the GAX February 2008 and it will upgrade the GAX bits while keeping everything working.

UPDATE: we're investigating the resulting state left by MSI Cleanup which sometimes doesn't properly remove all traces from the installed products thus making the new installation complete sucessfullybut without executing all the required steps. If after following 1) and 2) and after sucessfully installed GAX again the installation of GAT or any software factory fails with a message that GAX is not installed please run the following from a VS2005 or VS2008 command prompt (depending which version are you installing for if you're installing against just one):

For VS2005:

Installutil /ShowCallStack /i /DesignMode /Host=VisualStudio /hive=8.0 /Installer="Microsoft.Practices.RecipeFramework.VisualStudio.RecipeFrameworkInstaller, Microsoft.Practices.RecipeFramework.VisualStudio" "c:\Program Files\Microsoft Visual Studio 8\Common7\IDE\PublicAssemblies\Microsoft.Practices.RecipeFramework.dll"

For VS2008:

Installutil /ShowCallStack /i /DesignMode /Host=VisualStudio /hive=9.0 /Installer="Microsoft.Practices.RecipeFramework.VisualStudio.RecipeFrameworkInstaller, Microsoft.Practices.RecipeFramework.VisualStudio" "c:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\PublicAssemblies\Microsoft.Practices.RecipeFramework.dll"

If you're installing support for both VS you can just run what's specified for VS2005 above. Please make sure you just copy and paste the text so you don't miss any quotes and that you modify the path if you've installed VS on a folder different than the default one.

Links for downloads:

[1] http://download.microsoft.com/download/e/9/d/e9d80355-7ab4-45b8-80e8-983a48d5e1bd/msicuu2.exe

[2] http://softwarefactoriestoolkit.net/GaxTroubleshooter.zip