MainInstallLocation
This variable contains the primary installation folder of the main product, if the current installer is an add-on or upgrade installer as defined by the Add-on/Upgrade for product attribute on the Product info project page. If the current installer is not an add-on or upgrade installer, then its value is unknown.
Usage
You can refer to this variable as <MainInstallLocation>. Do not change its value; it has been carefully configured for cross-platform compatibility.
Related topics
MainInstalledVersion, MainProductCode, MainProductMaxVersion, MainProductMinVersion, Add-on installers