title: WIX Installer - Possible to Invoke Custom Action .exe Before `InstallFiles`?
body: <p>I have an .exe embedded inside my MSI installer which I'd like to somehow call directly from the installer, before the the 'InstallFiles' action occurs.</p>
  
  <p>It's defined as follows:</p>
  
  <pre><code>&lt;CustomAction Id="LaunchInstallManager_TryUninstall" Return="ignore" Directory="INSTALLFOLDER" Execute="deferred" Impersonate="no" ExeCommand="&amp;quot;[#fil713F8F6A7BC9B98857D779B9B29873E1]&amp;quot; /someargument"&gt;&lt;/CustomAction&gt;
  
  &lt;Custom Action="LaunchInstallManager_TryUninstall" Before="InstallFiles"&gt;NOT Installed&lt;/Custom&gt;
  </code></pre>
  
  <p>But upon looking at the logs, it looks like it's (trying to be) called from the install destination.</p>
  
  <p>Is such a thing possible?</p>