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.
The GUID, in combination with the version number (Product Version property), allows for release management of the product's files and registry keys.As a design feature, if applied correctly this mechanism will also roll back a failed uninstall of an application to a good working state.Windows Installer can advertise a product rather than actually install it.Important features such as rollback and versioning depend on a consistent internal database for reliable operation.Furthermore, Windows Installer facilitates the principle of least privilege by performing software installations by proxy for unprivileged users.Windows Installer contains significant changes from its predecessor, Setup API.
New features include a GUI framework and automatic generation of the uninstallation sequence.
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).
Similar to advertising, it installs a feature as soon as the user tries to use it.
An administrative installation is not a typical installation, in that it does not create any shortcuts, register COM servers, create an Add or Remove Programs entry, and so on.
Components can contain program files, folders, COM components, registry keys, and shortcuts.