Distributing a Windows Desktop App Safely from Japan — Code Signing and the SmartScreen Reality (2026)

"I want to distribute a Windows app, but I don't want security software to block it." For a Japanese company, the shortest path to meeting that requirement collapses to roughly two options: ship MSIX through the Microsoft Store, or sign an installer with a CA-issued code-signing certificate and serve it from your own site. But on Windows since 2024, buying an EV certificate no longer buys an instant SmartScreen bypass, and Microsoft's cheap cloud signing service, Azure Trusted Signing, excludes Japanese organizations. We assemble the 2026 realistic path end to end, from certificate selection through signing, distribution, and SmartScreen reputation operations.