When a Windows Installer setup is authored, it may be broken up into features. When self-healing or install-on-demand actions take place, they do so at the feature level. Keep in mind that when you repackage an application it is typically bundled into a single feature. This means that any missing key component (a file or registry entry set to trigger the install/repair-on-demand feature of the Windows Installer when found missing) will mean a complete reinstallation of your package. For this reason it is a good idea NOT to include HKCU keys in your package when they are not needed (they are rarely required- a well authored application should generate defaults if they do not exist) as these will be missing for each user who first runs the application- meaning everyone who uses the application will have to wait for a full installation to occur.