diff --git a/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
index 044353c0ae..1eecc84979 100644
--- a/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
+++ b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
@@ -152,10 +152,11 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#required' => TRUE,
       '#weight' => -20,
     ];
+    $default_site_mail = $this->config('system.site')->get('mail');
     $form['site_information']['site_mail'] = [
       '#type' => 'email',
       '#title' => $this->t('Site email address'),
-      '#default_value' => ini_get('sendmail_from'),
+      '#default_value' => empty($default_site_mail) ? ini_get('sendmail_from') : $default_site_mail,
       '#description' => $this->t("Automated emails, such as registration information, will be sent from this address. Use an address ending in your site's domain to help prevent these emails from being flagged as spam."),
       '#required' => TRUE,
       '#weight' => -15,
diff --git a/core/modules/system/src/Tests/Installer/InstallerSiteConfigDefaultTest.php b/core/modules/system/src/Tests/Installer/InstallerSiteConfigDefaultTest.php
index 1b2021ec6e..1117bea095 100644
--- a/core/modules/system/src/Tests/Installer/InstallerSiteConfigDefaultTest.php
+++ b/core/modules/system/src/Tests/Installer/InstallerSiteConfigDefaultTest.php
@@ -5,16 +5,28 @@
 use Drupal\simpletest\InstallerTestBase;
 
 /**
- * Verifies that the installer defaults to using the system timezone.
+ * Verifies that the installer defaults to using the system email address and
+ * timezone.
  *
  * @group Installer
  */
 class InstallerSiteConfigDefaultTest extends InstallerTestBase {
 
   /**
+   * {@inheritdoc}
+   */
+  protected function setUpSite() {
+    $this->assertFieldByName('site_mail', ini_get('sendmail_from'));
+    $this->assertFieldByName('date_default_timezone', @date_default_timezone_get());
+
+    return parent::setUpSite();
+  }
+
+  /**
    * Verify the correct site config was set.
    */
   public function testInstaller() {
+    $this->assertEqual(\Drupal::config('system.site')->get('mail'), $this->parameters['forms']['install_configure_form']['site_mail']);
     $this->assertEqual(\Drupal::config('system.date')->get('timezone.default'), @date_default_timezone_get());
   }
 
diff --git a/core/modules/system/src/Tests/Installer/InstallerSiteConfigProfileTest.php b/core/modules/system/src/Tests/Installer/InstallerSiteConfigProfileTest.php
index 588bd2e93f..421cb48936 100644
--- a/core/modules/system/src/Tests/Installer/InstallerSiteConfigProfileTest.php
+++ b/core/modules/system/src/Tests/Installer/InstallerSiteConfigProfileTest.php
@@ -13,31 +13,49 @@
 class InstallerSiteConfigProfileTest extends InstallerTestBase {
 
   protected $profile = 'testing_site_config';
+  protected $profile_site_mail = 'profile-testing-site-config@example.com';
+  protected $profile_timezone;
+
+  public function __construct($test_id = NULL) {
+    parent::__construct($test_id);
+
+    // The install profile set the timezone to one of two possibilities, but
+    // never to the system timezone. (See testing_site_config.install.)
+    $this->profile_timezone = 'America/Los_Angeles';
+    if ($this->profile_timezone == @date_default_timezone_get()) {
+      $this->profile_timezone = 'America/New_York';
+    }
+  }
 
   /**
    * {@inheritdoc}
    */
-   protected function installParameters() {
+  protected function installParameters() {
     $parameters = parent::installParameters();
 
-    // Don't override the site email address, which will default to the one from
-    // our install profile.
+    // Don't override the site email address, allowing it to default to the one
+    // from our install profile.
     unset($parameters['forms']['install_configure_form']['site_mail']);
 
     return $parameters;
   }
 
   /**
+   * {@inheritdoc}
+   */
+  protected function setUpSite() {
+    $this->assertFieldByName('site_mail', $this->profile_site_mail);
+    $this->assertFieldByName('date_default_timezone', $this->profile_timezone);
+
+    return parent::setUpSite();
+  }
+
+  /**
    * Verify the correct site config was set.
    */
   public function testInstaller() {
-    $this->assertEqual(\Drupal::config('system.site')->get('mail'), 'profile-testing-site-config@example.com');
-
-    // The install profile set the timezone to one of two possibilities, but
-    // never to the system timezone.
-    $timezone = \Drupal::config('system.date')->get('timezone.default');
-    $this->assertNotEqual($timezone, @date_default_timezone_get());
-    $this->assertTrue($timezone == 'America/Los_Angeles' || $timezone == 'America/New_York', 'Timezone is either Los Angeles or New York.');
+    $this->assertEqual(\Drupal::config('system.site')->get('mail'), $this->profile_site_mail);
+    $this->assertEqual(\Drupal::config('system.date')->get('timezone.default'), $this->profile_timezone);
   }
 
 }