Pure InstallScript projects rely on an internal PRODUCT_GUID variable. You can find and modify this definition in your project's view or directly within the setup script initialization rules. Best Practices for Product Code Management
A new panel added to the view in the InstallShield IDE: installshield product code
The Product Code should be treated with care. , as it breaks the link between the installer and the already-installed product. Once you change a project's GUID, its previous GUID cannot be recovered. If you change the Product Code without proper upgrade logic, Windows Installer treats the new version as an unrelated product, potentially leading to multiple entries in the "Add or Remove Programs" list and causing installation conflicts. Pure InstallScript projects rely on an internal PRODUCT_GUID
: When a user clicks "Uninstall" or "Change" in the Control Panel, Windows references this GUID to launch the correct MSI installer. Product Code vs. Upgrade Code vs. Package Code , as it breaks the link between the