Default Activity not found

Boa tarde,

estou tendo um problema recorrente, sempre que fecho o Android Studio e abro novamente e tento executar o projeto sempre me retorna: Error running 'app': Default Activity not found.

Sendo que acompanhei a aula e meu MainActivity e AndroidManifest estão semelhantes a das aulas.

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="br.com.aulas.agenda">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
</manifest>

MainActivity

package br.com.aulas.agenda;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        setTitle("Lista de Alunos");

        List<String> alunos = new ArrayList<>(Arrays.asList("Alex", "Fran", "José"));

        ListView listaDeAlunos = findViewById(R.id.activity_main_lista_de_alunos);
        listaDeAlunos.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, alunos));

    }
}

Gostaria de saber o que está acontecendo. Agradeço desde já

Estes são os dados do About do Android Studio

Android Studio 3.4.1
Build #AI-183.6156.11.34.5522156, built on May 1, 2019
JRE: 1.8.0_152-release-1343-b01 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 10 10.0