title: Using ManagedInstallerClass.InstallHelper to install multiple services
body: <p>I am currently trying to install multiple services using <strong>ManagedInstallerClass.InstallHelper</strong>.</p>
  
  <p>The code execution goes smoothly when I install the first service, then gives an error stating that a service with a same name already exists.
  However, if I exit the program then execute the same process starting from the second service, everything goes smoothly.</p>
  
  <p>The function I use is this one.</p>
  
  <pre><code>ManagedInstallerClass.InstallHelper(arguments.ToArray());
  </code></pre>
  
  <p>I am 100% sure that the arguments are correct.</p>
  
  <p>The exception I have is this one:</p>
  
  <pre><code>System.InvalidOperationException: "The installation failed, and the rollback has been performed."
  Inner Exception: "The specified service already exists"
  </code></pre>
  
  <p>My gut feeling is that the ManagedInstallerClass keeps something in its belly and thus when executing the second call in the same process something goes wrong.</p>
  
  <p>Anyone has an idea of what's happening and why?</p>