Windows Server AppFabric is installed and is not compatible with this release of Windows Azure AppFabric Developer Tools for Microsoft Visual Studio 2010 - June 2011 CTP. Please uninstall Windows Server AppFabric and rerun this setup if you want to install Windows Azure AppFabric Developer Tools for Microsoft Visual Studio 2010 - June 2011 CTP.When installing the Windows Azure AppFabric Tools for Visual Studio (found here), you might get the error message shown on the right, stating that Windows Server AppFabric is installed and that it is not compatible with this release of Windows Azure AppFabric Developer Tools for Microsoft Visual Studio 2010 – June 2011 CTP. It asks to uninstall Windows Server AppFabric and rerun this setup if you want to install Windows Azure AppFabric Developer Tools for Microsoft Visual Studio 2010 – June 2011 CTP.

When looking for the install of ‘Windows Server AppFabric’ to remove it through ‘Uninstall a program’ you won’t find this item in the list of installed programs. This might feel as a big problem heading your way…

Solution
This is, however, only a small problem on your way to Azure AppFabric development. Go to your list of installed programs and click ‘View installed updates’. Under Windows, you will find the update ‘Windows Server AppFabric (KB970622)’. Uninstall the update, restart your machine and try installing the Windows Azure AppFabric Tools for Visual Studio again…

Enjoy!