dart

Are you experiencing the “Could not find an option named no-sound-null-safety” error in Flutter?

We’re going to learn how to easily fix it in this article.

What causes the “Could not find an option named no-sound-null-safety” error?

The “Could not find an option named no-sound-null-safety” happens in a newer Flutter project using Dart 3.0, because Dart no longer supports unsound null safety.

Unsound null safety was a special Dart/Flutter feature where there are no static checks to ensure that we don’t access nullable variables – variables that may be null.

It allowed developers to migrate their codebase to the default null safety gradually without breaking existing code that depended on null-unsafe libraries.

But from version 3.0 upwards, Dart only supports code using sound null safety.

Fix “Could not find an option named no-sound-null-safety” (general)

To fix the “Could not find an option no-sound-null-safety” Flutter error, remove the --no-sound-null-safety option in your flutter run command.

Fix “Could not find an option named no-sound-null-safety” in VS Code

To fix the error in Visual Studio Code remove the --no-sound-null-safety option in the Dart: Flutter Additional Args setting.

You can use the Ctrl + , keyboard shortcut to quickly open the Settings page.