Hello,
It’s been a very long time I asked for help in forums the last time. Usually I can find solutions to my problems after spending some time on research, but not this time. I hope, someone is out there who can help me. 
I use Windows 8, Visual Studio 2010 Professional and the latest development version of MonoGame. I created one MonoGame project for my game and one Content project (which consists actually of two projects (XNA Content + Dummy project)).
I am currently developping a small game and I started working myself into the topics of effect files. So I created a new effects file test.fx and added it to my Content project (next to all the textures). In the properties, I set the “Content Processor” to “MonoGame effect” and compiled the Content project completely new. Everything worked so far.
But then, I wanted to use my new effects file and when I load it in the LoadContent I got an exception. I looked online for the exception’s cause and I found a forum topic about it. It was said, that this exception occurs, if the configuration of the Content project does not match to the game project. So I had a look at my console output when compiling the project and I saw this:
MonoGamePlatform:
MonoGame Platform PSM
SETX MONOGAME_PLATFORM "PSM" > NUL
I do not know why, but everytime I compile my Content project, it uses the PSM configuration! I set the configuration manually to Windows8 a dozen times, but it always compiles as PSM. I think that’s the reason, why I can’t use my effects file properly in my project.
Can you help me?