I found a problem in my app structure and build process using WebPack, TypeScript, and TS-Loader that I thought was caused by TypeScript 2.1.4, but apparently was there the whole time. You can see all the details from my other post: TypeScript 2.1.4 breaking changes in webpack ts-loader In short, I have Gulp and WebPack set to an entry point of /client/app.ts which for now has almost nothing in it (certainly nothing referencing /server/) but the TypeScript compilation stage of the WebPack build process is still trying to run on /server (and in my other post, showing a compilation error from