Since I use Fakes Framework in my UnitTest, I get the following MSBuild warning.
warning MSB3270: There was a mismatch between the processor architect
I have got a response from Microsoft for this issue
http://connect.microsoft.com/VisualStudio/feedback/details/804933/msb3270-mismatch-between-the-processor-architecture-fakes-framework
Visual Studio 2012:
Create the following element in “Fakes\MSBErrorTestClass.fakes” file under 'Fakes' node:
x86
Visual Studio 2013:
This issue has been fixed in the latest release i.e. Visual Studio 2013