diff --git a/app/helpers/export_helper.rb b/app/helpers/export_helper.rb
index a5268a789..b7a4d4def 100644
--- a/app/helpers/export_helper.rb
+++ b/app/helpers/export_helper.rb
@@ -851,7 +851,7 @@ module ExportHelper
   def make_zip_name(work, file_name="")
     Rails.logger.info("######################file_name: #{file_name}")
     # name = file_name === "" ? "" : (file_name[0, file_name.rindex('.')]+"_")
-    course = work&.homework_common.course || work&.graduation_task.course
+    course = work&.homework_common&.course || work&.graduation_task&.course
     "#{course&.user_group_name(work.user_id)}_#{work&.user&.student_id}_#{work&.user&.real_name}_#{Time.now.strftime('%Y%m%d_%H%M%S')}"
   end