[Vuejs]-Why does my Vue.js app not run when I use the runtime version of Vue?

If you look at the official documentation (https://v2.vuejs.org/v2/guide/installation.html#Explanation-of-Different-Builds) you will find a description about the different builds. So you are trying to use an UMD build (which is supposed to run in browser – not to be transformed by Webpack) in an ES environment. You should try vue.runtime.esm.js instead. By the way if you do not configure an alias for vue$ it should automatically pickup the right one – vue.runtime.esm.js