diff -u b/auto_entitylabel.module b/auto_entitylabel.module
--- b/auto_entitylabel.module
+++ b/auto_entitylabel.module
@@ -50,28 +50,30 @@
     /** @var \Drupal\auto_entitylabel\AutoEntityLabelManager $entity */
     $entity = $decorator->decorate($form_state->getFormObject()->getEntity());
 
-    if ($entity->hasAutoLabel()) {
-      $label = $entity->getLabelName();
-      $widget = &$form[$label]['widget'][0];
-      // Hide the label field. t will be automatically generated
-      // in hook_entity_presave().
-      $widget['value']['#type'] = 'hidden';
-      $widget['value']['#required'] = FALSE;
-      if (empty($widget['value']['#default_value'])) {
-        $widget['value']['#default_value'] = '%AutoEntityLabel%';
-      }
-    }
-    else {
-      if ($entity->hasOptionalAutoLabel()) {
+    if ($entity instanceof ContentEntityInterface) {
+      if ($entity->hasAutoLabel()) {
         $label = $entity->getLabelName();
         $widget = &$form[$label]['widget'][0];
-        // Allow label field to be empty. It will be automatically generated
-        // in hook_entity_presave().
+        // Hide the label field. It will be automatically generated in
+        // hook_entity_presave().
+        $widget['value']['#type'] = 'hidden';
         $widget['value']['#required'] = FALSE;
+        if (empty($widget['value']['#default_value'])) {
+          $widget['value']['#default_value'] = '%AutoEntityLabel%';
+        }
+      }
+      else {
+        if ($entity->hasOptionalAutoLabel()) {
+          $label = $entity->getLabelName();
+          $widget = &$form[$label]['widget'][0];
+          // Allow label field to be empty. It will be automatically generated
+          // in hook_entity_presave().
+          $widget['value']['#required'] = FALSE;
+        }
       }
-    }
 
-    $form['#auto_entitylabel_processed'] = TRUE;
+      $form['#auto_entitylabel_processed'] = TRUE;
+    }
   }
 }