Common causes:
1. Duplicate asset declarations
example:
assets\images\background.png
assets\images\background.png
2. Case mismatch on Windows
example:
assets\images\background.png
assets\images\Background.png
3. Stable build cache
Even if your assets are correct, a leftover copy in build/ or .dart_tool/ can trigger this error.
How to Fix?
1. Verify your pubspec.yaml only includes
flutter:
assets:
- assets\images\background.png
2. Delete build/ and .dart_tool/ manually before running again.
3. Run below command
flutter clean
flutter pub get
flutter run
4. App builds successfully!!!! no more PathExistsException. Hurrey 🎉