Index: src/wp-includes/theme.php
===================================================================
--- src/wp-includes/theme.php	(revision 39174)
+++ src/wp-includes/theme.php	(working copy)
@@ -1763,7 +1763,7 @@
  */
 function get_theme_starter_content() {
 	$theme_support = get_theme_support( 'starter-content' );
-	if ( ! empty( $theme_support ) ) {
+	if ( is_array( $theme_support ) && ! empty( $theme_support ) ) {
 		$config = $theme_support[0];
 	} else {
 		$config = array();
Index: tests/phpunit/tests/theme/getThemeStarterContent.php
===================================================================
--- tests/phpunit/tests/theme/getThemeStarterContent.php	(revision 0)
+++ tests/phpunit/tests/theme/getThemeStarterContent.php	(working copy)
@@ -0,0 +1,25 @@
+<?php
+
+/**
+ * @group themes
+ */
+class Tests_WP_Theme_Get_Theme_Starter_Content extends WP_UnitTestCase {
+
+
+	function test_add_theme_support_empty() {
+		add_theme_support( 'starter-content', array() );
+
+		$starter_content = get_theme_starter_content();
+
+		$this->assertEmpty( $starter_content );
+	}
+
+	function test_add_theme_support_single_param() {
+		add_theme_support( 'starter-content' );
+
+		$starter_content = get_theme_starter_content();
+
+		$this->assertEmpty( $starter_content );
+	}
+}
+