Build Hololens Exception

Exception: Failed to locate env variables VS140COMNTOOLS or VS120COMNTOOLS.
Utility.GetVSVersion () (at C:/buildslave/unity/build/PlatformDependent/WinRT/SharedSources/CSharp/Utility.cs:623)
MetroCSharpVisualStudioSolutionCreator.WriteSolutionFile (System.String solutionFileName, UnityEditor.Scripting.ScriptCompilation.ScriptAssembly[] csharpAssemblies) (at C:/buildslave/unity/build/PlatformDependent/MetroPlayer/Extensions/Managed/MetroCSharpVisualStudioSolutionCreator.cs:196)...

Build Hololens Exception