If you’ve seen following error when trying to build a Windows Azure Cloud Service Visual Studio 2010: “OutputPath property is not set for project 'CloudService1.ccproj'. Please check to make sure that you have specified a valid combination of Configuration and Platform for this project. Configuration='Debug' Platform='HPD'.” The solution is to delete the Platform environment variable that may’ve been added to your machine as it conflicts with an environment variable of the same name that MSBUILD uses. This environment variable is added on HP machines and does impact a number of different scenarios with Visual Studio and Expression Blend.
More info: Microsoft Connect