Why does Unity not find my parameterized constructor?

Question

My tiny, novice, Bootstrapper configures the container as follows:

protected override void ConfigureContainer()
{
    base.ConfigureContainer();
    RegisterTypeIfMissing(typeof(IUserSettingsProvider), typeof(JsonUserSettingsProvider), true);
    RegisterTypeIfMissing(typeof(IAppState), typeof(AppState), true);
    Container.RegisterType<TripleDesEncryptionService>(new InjectionConstructor(App.CryptoKey));
    Container.RegisterType<BaseViewModel>(new InjectionConstructor(Container.Resolve<IAppState>()));
}

and my BaseViewModel has only one ctor:

public abstract class BaseViewModel : BindableBase, INotifyPropertyChanged
{
    protected BaseViewModel(AppState appState)
    {
        AppState = appState;
    }
    ...
}

When I try and run the project, the bootstrapper fails on RegisterType<BaseViewModel> and throws the following exception.

System.InvalidOperationException: 'The type ApptEase.Client.Infrastructure.ViewModels.BaseViewModel does not have a constructor that takes the parameters (AppState).'

AppState is created and registered with the container in the application startup code:

protected override void OnStartup(StartupEventArgs e)
{
    base.OnStartup(e);
    var boot = new Bootstrapper();
    boot.Run();
    Container = boot.Container;
    _appState = new AppState();
    Container.RegisterInstance(typeof(AppState), _appState);
}

Answer 1

Your BaseViewModel class constructor is protected. Which is not visible to Unity. But anyway, as user 3615 wrote in comments -

You cannot resolve abstract class since instance cannot be created

So I would suggest explicitly registering a concrete implementation instance and mapping it to that base type.

Container.RegisterInstance(typeof(BaseViewModel), new MyConcreteViewModel());

But in the end what you want is actually an interface typed registration. That unlocks testability via mocking.