I just encountered something I thought was odd - Visual Studio 2015 Enterprise was complaining when trying to create a new C# unit test project. It might be because I'm on Windows 10, I don't know - I only run Windows 10 for development now.

The error was :

Error: Could not load file or assembly Microsoft.VisualStudio.JSLS Version=


  1. Mount the VS 2015 ISO
  2. Run E:\packages\JavaScript_LanguageService\JavaScript_LanguageService.msi
  3. Restart Visual Studio