diff --git a/core/modules/comment/comment.module b/core/modules/comment/comment.module
index 4978551..f277a02 100644
--- a/core/modules/comment/comment.module
+++ b/core/modules/comment/comment.module
@@ -351,8 +351,8 @@ function comment_form_field_ui_field_storage_edit_form_alter(&$form, FormStateIn
   if ($form['#field']->getType() == 'comment') {
     // We only support posting one comment at the time so it doesn't make sense
     // to let the site builder choose anything else.
-    $form['field']['cardinality_container']['cardinality']['#options'] = array(1 => 1);
-    $form['field']['cardinality_container']['#access'] = FALSE;
+    $form['field_storage']['cardinality_container']['cardinality']['#default_value'] = 1;
+    $form['field_storage']['cardinality_container']['#access'] = FALSE;
   }
 }
 
diff --git a/core/modules/comment/src/Tests/CommentNonNodeTest.php b/core/modules/comment/src/Tests/CommentNonNodeTest.php
index 704a298..280e0f8 100644
--- a/core/modules/comment/src/Tests/CommentNonNodeTest.php
+++ b/core/modules/comment/src/Tests/CommentNonNodeTest.php
@@ -244,8 +244,14 @@ function testCommentFunctionality() {
     $this->assertText(t('Comments'));
     $this->assertLinkByHref('entity_test/structure/entity_test/fields/entity_test.entity_test.comment');
     // Test widget hidden option is not visible when there's no comments.
-    $this->drupalGet('entity_test/structure/entity_test/entity-test/fields/entity_test.entity_test.comment');
+    $this->drupalGet('entity_test/structure/entity_test/fields/entity_test.entity_test.comment');
+    $this->assertResponse(200);
     $this->assertNoField('edit-default-value-input-comment-und-0-status-0');
+    // Test that field to change cardinality is not available.
+    $this->drupalGet('entity_test/structure/entity_test/fields/entity_test.entity_test.comment/storage');
+    $this->assertResponse(200);
+    $this->assertNoField('field_storage[cardinality_number]');
+    $this->assertNoField('field_storage[cardinality]');
 
     $this->drupalLogin($this->adminUser);
 
@@ -382,6 +388,7 @@ function testCommentFunctionality() {
     $field_storage = entity_load('field_storage_config', 'entity_test.field_barfoo');
     $this->assertTrue($field_storage);
     $this->assertEqual($field_storage->getSetting('comment_type'), 'foobar');
+    $this->assertEqual($field_storage->getCardinality(), 1);
 
     // Test the new entity commenting inherits default.
     $random_label = $this->randomMachineName();