MSIX

MSIX is a Windows packaging format and deployment technology developed by Microsoft to modernize software distribution on Windows. It consolidates features of previous packaging technologies, including MSI installers, AppX, App-V, and ClickOnce, into a single, secure package model. The goal is reliable, predictable installations and clean removals, with reduced conflicts between applications.

MSIX packages are distributed as MSIX bundles or single packages (.msix, .msixbundle). Older formats such as AppX (.appx, .appxbundle) are supported for compatibility. Each package contains the application, its dependencies, and a manifest that describes installation behavior. Packages run in a containerized environment to limit system-wide changes and support per-user or per-machine installation, with dependency resolution and configuration options.

Deployment can occur through the Microsoft Store, enterprise distribution channels, or sideloading via the App Installer tool. App Installer uses an .appinstaller manifest to locate a package, check versions, and manage updates. Updates are delivered as MSIX bundles and installed atomically to minimize mid-install state issues.

Security and management: MSIX relies on code signing and trusted certificates to ensure authenticity. Containerization helps isolate applications from the rest of the system, reducing conflicts and cleanup issues during uninstall. MSIX supports enterprise deployment scenarios and is available on Windows 10 and later as part of Microsoft's packaging strategy for modern Windows apps.