This process is known as self-healing or self-repair. The user interface phase typically queries the target system, displays an installation wizard and enables the user to change various options that will affect the installation.However, the user interface sequence should not make any changes to the system, for the following reasons: When the user clicks the "Install" button in a typical MSI installation wizard, installation proceeds to the Execute phase, in which software components are actually installed.As a design feature, if applied correctly this mechanism will also roll back a failed uninstall of an application to a good working state.
A package includes the package logic and other metadata that relates to how the package executes when running.
For example, changing an EXE file in the product may require the Product Code or Product Version to be changed for the release management.
In case any script action fails during deferred execution, or the operation is cancelled by the user, all the actions performed until that point are rolled back, restoring the system to its original state.
Standard Windows Installer actions automatically write information into a rollback script; package authors who create custom actions that change the target system should also create corresponding rollback actions (as well as uninstall actions and uninstallation-rollback actions).
) is a software component and application programming interface (API) of Microsoft Windows used for the installation, maintenance, and removal of software.
The installation information, and optionally the files themselves, are packaged in installation packages, loosely relational databases structured as COM Structured Storages and commonly known as "MSI files", from their default filename extensions.
Components are identified globally by GUIDs; thus the same component can be shared among several features of the same package or multiple packages, ideally through the use of Merge Modules.
A key path is a specific file, registry key, or ODBC data source that the package author specifies as critical for a given component.
Some MSI packages authored in Install Shield may prevent the use of these and other native MSI features.
The user must have administrator privileges to complete the advertised installation.
Windows Installer contains significant changes from its predecessor, Setup API.