title: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests
body: <p>I'm attempting to start an .NET Core 2/Angular 6 SPA. I created an Angular 5 Application using &quot;dotnet new angular&quot; then proceeded to upgrade using <a href="https://update.angular.io/" rel="noreferrer">this guide</a> from angular.io. Once I finished the upgrade I tried to run the application using &quot;dotnet run&quot; and I get an ugly error page with the error:</p>
  <blockquote>
  <p><strong>An unhandled exception occurred while processing the request.</strong></p>
  <p>AggregateException: One or more errors occurred. (One or more errors
  occurred. (The NPM script 'start' exited without indicating that the
  Angular CLI was listening for requests. The error output was: Unknown
  option: '--extractCss'</p>
  <p>InvalidOperationException: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown  option: '--extractCss'</p>
  </blockquote>
  <p>Thinking perhaps I missed a step during the upgrade, I tried a second time and got the same error.</p>
  <p>Here are the steps I took after creating the app:</p>
  <pre><code>npm install -g @angular/cli
  npm install @angular/cli
  ng update @angular/cli
  ng update @angular/core
  npm install --save @angular/material @angular/cdk @angular/animations hammerjs 
  npm install -g rxjs-tslint
  rxjs-5-to-6-migrate -p src/tsconfig.app.json
  </code></pre>
  <p>I'm running Node version 9.4.0 and .Net Core 2.1.200 on Windows 10 (1703) Enterprise.</p>
  <p>Any ideas on how to fix this? Here is a full stack trace:</p>
  <pre><code> ---&gt; System.IO.EndOfStreamException: Attempted to read past the end of the stream.
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()
     --- End of inner exception stack trace ---
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()
     --- End of inner exception stack trace ---
     at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;&gt;c.&lt;Attach&gt;b__2_0(Task`1 task)
     at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
     at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task&amp; currentTaskSlot)
     --- End of inner exception stack trace ---
     at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
     at Microsoft.AspNetCore.SpaServices.Extensions.Util.TaskTimeoutExtensions.&lt;WithTimeout&gt;d__1`1.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.SpaServices.Extensions.Proxy.SpaProxy.&lt;PerformProxyRequest&gt;d__4.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.Builder.SpaProxyingExtensions.&lt;&gt;c__DisplayClass2_0.&lt;&lt;UseProxyToSpaDevelopmentServer&gt;b__0&gt;d.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.Builder.RouterMiddleware.&lt;Invoke&gt;d__4.MoveNext()
  --- End of stack trace from previous location where exception was thrown ---
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.&lt;Invoke&gt;d__7.MoveNext()
  ---&gt; (Inner Exception #0) System.AggregateException: One or more errors occurred. (The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'
  
  ) ---&gt; System.InvalidOperationException: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'
  
   ---&gt; System.IO.EndOfStreamException: Attempted to read past the end of the stream.
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()
     --- End of inner exception stack trace ---
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()
     --- End of inner exception stack trace ---
     at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;&gt;c.&lt;Attach&gt;b__2_0(Task`1 task)
     at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
     at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
     at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task&amp; currentTaskSlot)
  ---&gt; (Inner Exception #0) System.InvalidOperationException: The NPM script 'start' exited without indicating that the Angular CLI was listening for requests. The error output was: Unknown option: '--extractCss'
  
   ---&gt; System.IO.EndOfStreamException: Attempted to read past the end of the stream.
     at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()
     --- End of inner exception stack trace ---
     at Microsoft.AspNetCore.SpaServices.AngularCli.AngularCliMiddleware.&lt;StartAngularCliServerAsync&gt;d__3.MoveNext()&lt;---
  &lt;---
  </code></pre>