title: Prevent .NET config file being overwritten during install
body: <p>I'm using InstallShield 2010 Express to install a .NET WinForms app. The latest InstallShield project is a major upgrade, so I've used the Upgrade Paths section to allow upgrades from earlier versions of my app. </p>
  
  <p>The problem is that config settings made during the initial install (written to Program Files\MyCompany\MyApp\myapp.exe.config) are being overwritten when installing the latest upgrade. This means that the user has to make all of the config settings again - not good.</p>
  
  <p>In the InstallShield project, myapp.exe.config is set to use <a href="http://msdn.microsoft.com/en-us/library/aa368599%28VS.85%29.aspx" rel="nofollow noreferrer">Windows Installer Versioning Rules</a>. I've even tried setting the create/mod date of myapp.exe.config very old (1/1/1999) so that it shouldn't overwrite the file on the target system.</p>
  
  <p>Other than this the installer works fine. How can I prevent this file from being overwritten?</p>