title: Execute application through custom URI in UWP
body: <p><strong>Update:</strong> By adding ":" next to app3 when calling it I no longer get the error, however the app is still not launched, instead I get an error message telling me I need a new application to open app3, how can I solve this? Why can't I simply open the app?</p>
  
  <p>I've got an applicacion <code>app3</code> that doens't do anything other than just opening a blank page. <a href="https://i.stack.imgur.com/dsWRY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dsWRY.png" alt="&lt;code&gt;app3&lt;/code&gt;"></a></p>
  
  <p>From another application <code>app4</code> I'm trying to call <code>app3</code></p>
  
  <pre><code>public MainPage()
      {
          this.InitializeComponent();
          callUri();
  
      }
  
      private async void callUri()
      {
          var uriBing = new Uri(@"app3");
  
          // Launch the URI
          var success = await Windows.System.Launcher.LaunchUriAsync(uriBing);
      }
  </code></pre>
  
  <p>But am getting the folling error message: </p>
  
  <p><code>System.UriFormatException: 'Invalid URI: The format of the URI could not be determined.'</code></p>
  
  <p>What exactly am I doing wrong? The Windows documentation for URI handling doens't really how how to call custom URI, only their premade ones, and I haven't seen any other questions regarding this. The App3 packages have already been created. </p>