Often I’m asked why installing a Windows Installer patch (MSP) takes as long or longer to install than the target product (MSI). While this isn’t always the case for every patch, it’s certainly possible for a number of reasons.
Shared components define shared resources. It might seem obvious, but it’s important to understand that whatever you do to a shared resource during the installation of one product affects those same resources for any other product. For example,
Major upgrades are Windows Installer products that can be installed like any other product with the added benefit of removing one ore more related products. For example, version 2 of a product can be installed on a clean machine, or on a machine with version 1 already installed and will remove version 1.
When testing the serviceability of your product before you ship, it’s important to test any conditions you might have on the product, features, components, and actions.
Feature conditions can set the install level of a feature when the package is installed.
It’s always important to test your product before it ships. Servicing it later can prove very costly and very difficult. It’s no different with your installation packages. You need to test not only basic install and uninstall operations, but also test your servicing plan.