diff --git a/core/modules/contact/lib/Drupal/contact/CategoryListController.php b/core/modules/contact/lib/Drupal/contact/CategoryListController.php
index 3177103..59d865c 100644
--- a/core/modules/contact/lib/Drupal/contact/CategoryListController.php
+++ b/core/modules/contact/lib/Drupal/contact/CategoryListController.php
@@ -130,6 +130,7 @@ public function buildForm(array $form, array &$form_state) {
         '#default_value' => ($default_category == $entity->id() ? $entity->id() : NULL),
         '#parents' => array('default_category'),
         '#id' => 'edit-entities-default',
+        '#disabled' => $entity->id() == 'personal',
       );
       // Add weight column and ordering.
       $row['#weight'] = $entity->get('weight');