title: Why am I getting this error after angular cli update
body: <p>Updated to latest angular and getting following error when I run <code>ng serve</code>. I couldn't understand what would be the issue.</p>
  
  <pre><code>Could not find module "@angular-devkit/build-angular" from "F:\\angular\\July\\FinalTest".
  Error: Could not find module "@angular-devkit/build-angular" from "F:\\angular\\July\\FinalTest".
  
      at Object.resolve (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\@angular-devkit\core\node\resolve.js:141:11)
      at Observable.rxjs_1.Observable [as _subscribe] (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\@angular-devkit\archit
  ect\src\architect.js:132:40)
      at Observable._trySubscribe (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:43:25)
      at Observable.subscribe (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:29:22)
      at DoOperator.call (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\tap.js:29:23)
      at Observable.subscribe (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\Observable.js:24:22)
      at C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\util\subscribeTo.js:22:31
      at Object.subscribeToResult (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\util\subscribeToResult.js:7:
  45)
      at MergeMapSubscriber._innerSub (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\mergeMap.js:75
  :38)
      at MergeMapSubscriber._tryNext (C:\Users\User\AppData\Roaming\npm\node_modules\@angular\cli\node_modules\rxjs\internal\operators\mergeMap.js:72:
  14)
  </code></pre>
  
  <p><code>ng -v</code> command display</p>
  
  <pre><code>    Angular CLI: 6.1.1
  Node: 8.11.3
  OS: win32 x64
  Angular: 6.1.0
  ... animations, common, compiler, core, forms, http
  ... platform-browser, platform-browser-dynamic, router
  
  Package                         Version
  ---------------------------------------------------------
  
  @angular-devkit/architect       0.7.1 (cli-only)
  @angular-devkit/build-angular   &lt;error&gt;
  @angular-devkit/core            0.7.1 (cli-only)
  @angular-devkit/schematics      0.7.1 (cli-only)
  @angular/cli                    &lt;error&gt;
  @angular/compiler-cli           &lt;error&gt;
  @angular/language-service       &lt;error&gt;
  @schematics/angular             0.7.1 (cli-only)
  @schematics/update              0.7.1 (cli-only)
  rxjs                            6.2.2
  typescript                      2.7.2 (cli-only)
  </code></pre>
  
  <p>How could I fix this. Please help me someone</p>