title: UnrealBuildTool Exception: ERROR : failed to harvest environment variables
body: <p>I am new to dealing with these ERRORS so I need to know every step between getting this error while trying to open a project in unreal editor to having it actually open correctly in Windows 10. I had the same error in Windows 8.1 and in every version of UE4 since 4.9. I went back to it recently because I have been working with Maya since I am new to that as well. I use Visual Studio Community 2015. I can open a blueprint in UE4, but not a C++ Project.</p>
  
  <p>An error occurred while trying to generate project files.</p>
  
  <p>Running C:/Program Files (x86)/Epic Games/4.10/Engine/Binaries/DotNET/UnrealBuildTool.exe  -projectfiles -project="C:/Users/Corey/Documents/UE4Projects/Puzzle/Puzzle.uproject" -game -rocket -progress -2015
  Discovering modules, targets and source code for game...</p>
  
  <p>UnrealBuildTool Exception: ERROR : failed to harvest environment variables</p>