I am unable to compile/build anything within Visual Studio C++ 2012 because I am getting an error that states either I have an inappropriate ToolsVersion or that the ToolSet is missing.
Here is the error in the console:
Project file contains ToolsVersion="12.0". This toolset may be unknown or missing, in which case you may be able to resolve this by installing the appropriate version of MSBuild, or the build may have been forced to a particular ToolsVersion for policy reasons. Treating the project as if it had ToolsVersion="4.0".
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V110\Microsoft.Cpp.Platform.targets(44,5): error MSB8020: The builds tools for v120 (Platform Toolset = 'v120') cannot be found. To build using the v120 build tools, either click the Project menu or right-click the solution, and then select "Update VC++ Projects...". Install v120 to build using the v120 build tools.
I have installed Microsoft SDK. This may be relevant also - I downgraded from 2013 VSRC to 2012 MSVC recently but I made a clean uninstallation.
Try Microsoft Build Tools 2013 for building ToolsVersion="12.0" projects here:
http://www.microsoft.com/en-au/download/details.aspx?id=40760
It might help you get going.
Project -> Properties -> General -> Platform Toolset (as IInspectable correctly commented)
<Project DefaultTargets="Build" ToolsVersion="12.0" ...
<Project DefaultTargets="Build" ToolsVersion="4.0" ...