Prerequisites are a great thing in InstallShield. They are self-contained entities that install a specific technology. Examples are the Windows Installer, the .NET Framework and SQL Server 2008 Express. There are two types of prerequisites, setup and feature. Let’s look at each type.
Setup Prerequisites are installed before the main installation occurs. To use Setup Prerequisites, you must have a release that includes Setup.exe. It acts as the bootstrapper that installs the prerequisites and handles any reboots. Setup Prerequisites are available in Basic MSI, InstallScript MSI and InstallScript projects.
A Feature Prerequisite is a bit different. Here, the prerequisite is assigned to a feature and installed during the main installation. The advantage is that you can add conditions to features, which can be used to control whether or not they are available for installation.
The most important thing you need to remember with Feature Prerequisites is this:
They are not available in InstallScript MSI projects, even though that project type is based on the Windows Installer.