npm start error with create-react-app

It seems like you don't have react-scripts in your global environment. Two possibility are available here :

npm install -g react-scripts

or in your package.json change your script part like this :

  "scripts": {
    "start": "./node_modules/react-scripts/bin/react-scripts.js start",
    "start:prod": "pushstate-server build",
    "build": "./node_modules/react-scripts/bin/react-scripts.js build",
    "test": "./node_modules/react-scripts/bin/react-scripts.js test --env=jsdom",
    "eject": "./node_modules/react-scripts/bin/react-scripts.js eject",
    "server": "cd client/api && pm2 start server.js --watch",
    "proxy": "http://128.199.139.144:3000"
  },

Author of Create React App checking in.

You absolutely should not be installing react-scripts globally.
You also don't need ./node_modules/react-scripts/bin/ in package.json as this answer implies.

If you see this:

npm ERR! [email protected] start: `react-scripts start`
npm ERR! spawn ENOENT

It just means something went wrong when dependencies were installed the first time.

I suggest doing these three steps:

1. npm install -g npm@latest to update npm because it is sometimes buggy.
2. rm -rf node_modules to remove the existing modules.
3. npm install to re-install the project dependencies.

This should fix the problem.
If it doesn't, please file an issue with a link to your project and versions of Node and npm.