title: Abort Merge Module installation
body: <p>I have a .msi that was recently transformed into a .msm and became component of a larger .msi.</p>
  
  <p>I have a Custom Action that aborts installation at downgrade.</p>
  
  <pre><code>&lt;Custom Action="AbortDowngrade" After="InstallChecks"&gt;INSTALLED_BUILDNO &amp;gt; INSTALLING_BUILDNO&lt;/Custom&gt;
  </code></pre>
  
  <p>defined as:</p>
  
  <pre><code>&lt;CustomAction Id="AbortDowngrade" Error="Downgrade not allowed"/&gt;
  </code></pre>
  
  <p>The Custom Action is type 19 and causes entire .msi to abort. </p>
  
  <p>How can I update the .msm so it fails gracefully without affecting the .msi?</p>
  
  <p>Thanks!</p>