Run the installer and wait until it finishes downloading the main files but it completes the installation.
The most reliable official source for legacy full installers is the Kaspersky Product Repository. Although it may appear empty initially, you can navigate by selecting the product, country, and version from the dropdown menus.
Finding a can be a challenge, as most official Kaspersky download pages primarily offer "online" stubs that download necessary files during installation. However, offline installers are essential for users with limited bandwidth or those needing to install protection on multiple disconnected machines. Official Ways to Get Offline Installers
How to install and activate Kaspersky Internet Security 2018
