Kaspersky Total Security has the best heuristic detection when completely disconnected from the internet. It does not rely on "cloud lookups" as heavily as competitors.
Sometimes Windows Defender blocks offline installers because they modify security settings. Right-click the system tray shield > "Virus & threat protection" > "Manage settings" > Turn off "Real-time protection" (it will turn back on after reboot automatically). kaspersky total security offline installer hot