UWP apps
UWP apps explained
UWP stands for Universal Windows Platform. It is the modern app model that Microsoft built to run a single package across Windows PCs, HoloLens, and the Xbox family. Because Xbox One and Windows share this runtime, a developer can compile one project and ship a build that installs on the console with very few changes.
What a package contains
A UWP app is delivered as a signed bundle, typically an .appxbundle, that wraps the executable, its libraries, assets, and a manifest. The manifest declares the app's identity, the capabilities it requests, and which hardware it targets. When you sideload in Dev Mode, the console reads this manifest to decide what the app is allowed to do.
The sandbox
Every UWP app runs isolated from the system and from other apps. It gets its own private data folders for settings and save files, but it is walled off from the rest of the console. Crucially, an app cannot write to its own install directory, so anything it needs to modify must go elsewhere.
| Trait | Effect |
|---|---|
| Sandboxed | Isolated from system and other apps |
| Size cap | 2 GB maximum per installed app |
| Capabilities | Requested in the manifest, such as broad file access |
Understanding this model explains why emulators ask you to enable extra file permissions and why your content usually lives on USB rather than inside the app.
UWP Sandbox