"Port 4200 is already in use". Killing all the processes associated with 4200 did not work.
<p>I'm trying to get angular running on my Mac OS X 10.11.3 El Capitan.</p>

<p>I installed nodeJS and npm. Through npm I installed angular-cli.</p>

<p>I created a new app via the command <code>sudo ng new first-app</code></p>

<p>I navigated into the app folder and ran <code>sudo ng serve</code>. </p>

<p>It threw the following error : </p>

<pre><code>Could not start watchman; falling back to NodeWatcher for file system events.
Visit http://ember-cli.com/user-guide/#watchman for more info.
Port 4200 is already in use.
</code></pre>

<p>With reference from another answer, I tried the following :</p>

<pre><code>sudo kill $(sudo lsof -t -i:4200)
</code></pre>

<p>It did not help.</p>

<p>Actually, I have re-installed nodejs, npm, angular-cli. When I had installed it before there was some build error as there was some bower issue. Not sure what. When I accessed localhost:4200 that time, the page showed up but with the error log on it. Now the page doesn't even load. The loading symbol just keeps circling near the favicon. I don't know if this could be a lead. </p>

<p>Thanks. I need to get angular running pronto. Lots to learn !</p>