Index: branches/5.2.x/core/units/categories/categories_event_handler.php
===================================================================
--- branches/5.2.x/core/units/categories/categories_event_handler.php
+++ branches/5.2.x/core/units/categories/categories_event_handler.php
@@ -1813,9 +1813,6 @@
 			$object = $event->getObject();
 			/* @var $object CategoriesItem */
 
-			$object->checkFilename();
-			$object->generateFilename();
-
 			$now = adodb_mktime();
 
 			if ( !$this->Application->isDebugMode() && strpos($event->Special, 'rebuild') === false ) {
@@ -1830,6 +1827,9 @@
 				}
 			}
 
+			$object->checkFilename();
+			$object->generateFilename();
+
 			// Don't allow creating records on behalf of another user.
 			if ( !$this->Application->isAdminUser && !defined('CRON') ) {
 				$object->SetDBField('CreatedById', $object->GetOriginalField('CreatedById'));