diff --git a/config/paths.js b/config/paths.js
index bb1ba761258..c3594e14519 100644
--- a/config/paths.js
+++ b/config/paths.js
@@ -39,6 +39,7 @@ var nodePaths = (process.env.NODE_PATH || '')
 module.exports = {
   appBuild: resolveApp('build'),
   appHtml: resolveApp('index.html'),
+  appIndexJs: resolveApp('src/index.js'),
   appPackageJson: resolveApp('package.json'),
   appSrc: resolveApp('src'),
   testsSetup: resolveApp('src/setupTests.js'),
@@ -56,6 +57,7 @@ function resolveOwn(relativePath) {
 module.exports = {
   appBuild: resolveApp('build'),
   appHtml: resolveApp('index.html'),
+  appIndexJs: resolveApp('src/index.js'),
   appPackageJson: resolveApp('package.json'),
   appSrc: resolveApp('src'),
   testsSetup: resolveApp('src/setupTests.js'),
@@ -70,6 +72,7 @@ module.exports = {
 module.exports = {
   appBuild: resolveOwn('../build'),
   appHtml: resolveOwn('../template/index.html'),
+  appIndexJs: resolveOwn('../template/src/index.js'),
   appPackageJson: resolveOwn('../package.json'),
   appSrc: resolveOwn('../template/src'),
   testsSetup: resolveOwn('../template/src/setupTests.js'),
diff --git a/config/webpack.config.dev.js b/config/webpack.config.dev.js
index 86f592ba5b8..a88409f2d05 100644
--- a/config/webpack.config.dev.js
+++ b/config/webpack.config.dev.js
@@ -49,7 +49,7 @@ module.exports = {
     // We ship a few polyfills by default.
     require.resolve('./polyfills'),
     // Finally, this is your app's code:
-    path.join(paths.appSrc, 'index')
+    paths.appIndexJs
     // We include the app code last so that if there is a runtime error during
     // initialization, it doesn't blow up the WebpackDevServer client, and
     // changing JS code would still trigger a refresh.
diff --git a/config/webpack.config.prod.js b/config/webpack.config.prod.js
index 2a482f9547e..552ded48551 100644
--- a/config/webpack.config.prod.js
+++ b/config/webpack.config.prod.js
@@ -48,7 +48,7 @@ module.exports = {
   // In production, we only want to load the polyfills and the app code.
   entry: [
     require.resolve('./polyfills'),
-    path.join(paths.appSrc, 'index')
+    paths.appIndexJs
   ],
   output: {
     // The build folder.
diff --git a/scripts/build.js b/scripts/build.js
index e60b554466f..71dcc798bba 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -21,9 +21,12 @@ var rimrafSync = require('rimraf').sync;
 var webpack = require('webpack');
 var config = require('../config/webpack.config.prod');
 var paths = require('../config/paths');
+var checkRequiredFiles = require('./utils/checkRequiredFiles');
 var recursive = require('recursive-readdir');
 var stripAnsi = require('strip-ansi');
 
+checkRequiredFiles();
+
 // Input: /User/dan/app/build/static/js/main.82be8.js
 // Output: /static/js/main.js
 function removeFileNameHash(fileName) {
diff --git a/scripts/eject.js b/scripts/eject.js
index 3e5e18af387..74c5c9ef99b 100644
--- a/scripts/eject.js
+++ b/scripts/eject.js
@@ -44,6 +44,7 @@ prompt(
     path.join('config', 'jest', 'transform.js'),
     path.join('scripts', 'build.js'),
     path.join('scripts', 'start.js'),
+    path.join('scripts', 'utils', 'checkRequiredFiles.js'),
     path.join('scripts', 'utils', 'chrome.applescript'),
     path.join('scripts', 'utils', 'prompt.js'),
     path.join('scripts', 'utils', 'WatchMissingNodeModulesPlugin.js')
diff --git a/scripts/start.js b/scripts/start.js
index be1d6f80e0d..84d1e7c4b48 100644
--- a/scripts/start.js
+++ b/scripts/start.js
@@ -20,6 +20,7 @@ var httpProxyMiddleware = require('http-proxy-middleware');
 var execSync = require('child_process').execSync;
 var opn = require('opn');
 var detect = require('detect-port');
+var checkRequiredFiles = require('./utils/checkRequiredFiles');
 var prompt = require('./utils/prompt');
 var config = require('../config/webpack.config.dev');
 var paths = require('../config/paths');
@@ -180,7 +181,7 @@ function onProxyError(proxy) {
       ' from ' + chalk.cyan(host) + ' to ' + chalk.cyan(proxy) + '.'
     );
     console.log(
-      'See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (' + 
+      'See https://nodejs.org/api/errors.html#errors_common_system_errors for more information (' +
       chalk.cyan(err.code) + ').'
     );
     console.log();
@@ -190,7 +191,7 @@ function onProxyError(proxy) {
     if (res.writeHead && !res.headersSent) {
         res.writeHead(500);
     }
-    res.end('Proxy error: Could not proxy request ' + req.url + ' from ' + 
+    res.end('Proxy error: Could not proxy request ' + req.url + ' from ' +
       host + ' to ' + proxy + ' (' + err.code + ').'
     );
   }
@@ -304,6 +305,7 @@ function runDevServer(port, protocol) {
 
 function run(port) {
   var protocol = process.env.HTTPS === 'true' ? "https" : "http";
+  checkRequiredFiles();
   setupCompiler(port, protocol);
   runDevServer(port, protocol);
 }
diff --git a/scripts/utils/checkRequiredFiles.js b/scripts/utils/checkRequiredFiles.js
new file mode 100644
index 00000000000..8110eb01cdb
--- /dev/null
+++ b/scripts/utils/checkRequiredFiles.js
@@ -0,0 +1,33 @@
+// @remove-on-eject-begin
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+// @remove-on-eject-end
+
+const fs = require('fs');
+const path = require('path');
+const chalk = require('chalk');
+const paths = require('../../config/paths');
+
+function checkRequiredFiles() {
+  const filesPathToCheck = [paths.appHtml, paths.appIndexJs];
+  filesPathToCheck.forEach(filePath => {
+    try {
+      fs.accessSync(filePath, fs.F_OK);
+    } catch (err) {
+      const dirName = path.dirname(filePath);
+      const fileName = path.basename(filePath);
+      console.log(chalk.red('Could not find a required file.'));
+      console.log(chalk.red('  Name: ') + chalk.cyan(fileName));
+      console.log(chalk.red('  Searched in: ') + chalk.cyan(dirName));
+      process.exit(1);
+    }
+  });
+}
+
+module.exports = checkRequiredFiles;