I’m not sure what the problem is if none of my solutions help BUT you have to manually compile the project before you can open it. That’s why you can’t open the editor.
As I said if you’re using Visual Studio 2015, stop using Visual Studio 2015 or at least with UE4. Download and install Visual Studio 2013. For now you can only really use 2013 for UE4 as 2015 is not fully supported if at all.
Once you’ve done all that, open the project in Visual Studio 2013, if it won’t compile right click on your project in the solution explorer and go to properties, or select it and hit Enter + alt.
In Properties in VC++ Directories set the empty fields to “inherit from parent or project” Then try to build again and it should work.
Every time I make a C++ Project, I get the same error message. And every time this is how I fix it. If none of this helps then I’m fresh out of ideas.