ApplicationData API not working for unpackaged WinAppSDK App

[Illustar0]

Current behavior 🐛

When attempting to access Windows.Storage.ApplicationData APIs (e.g., ApplicationData.Current.LocalFolder) within a WinAppSDK project running in Unpackaged mode, the application crashes immediately.

The following exception is thrown: System.InvalidOperationException: Operation is not valid due to the current state of the object.

Expected behavior 🎯

The application should handle the missing Package Identity gracefully. Ideally, Uno Platform should abstract this difference and fallback to a standard local file path, or throw a more descriptive exception indicating that ApplicationData is not supported in Unpackaged mode without a Sparse Package.

How to reproduce it (as minimally and precisely as possible) 🔬

Adding any ApplicationData API code to any WinAppSDK project and running it as unpackaged results in the error: Operation is not valid due to the current state of the object.

Workaround 🛠️

N/A

Renderer 🎨

• Skia
• Native

Affected platforms 📱💻🖥️

Windows App SDK

Uno.Sdk version (and other relevant versions) 📦

6.4.42

IDE version 🧑‍💻

Rider 2025.3.0.3

Anything else we need to know? 💬

N/A