How offline license activation actually works

If you ship a desktop app outside an app store, you eventually hit the same wall: how do you check a license when the user is on a plane, behind a corporate firewall, or just offline? Calling your server on every launch isn't an option. Here's how offline activation actually works, without the hand-waving. The first thing everyone reaches for is "call home on launch, get back yes/no." It works in the demo and fails in the wild: No network = no app. Fail-closed locks out paying customers.