diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 87dc127a0..c13039696 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -3200,6 +3200,7 @@ class UsersController < ApplicationController
         ori = Attachment.find_by_id(send_id)
         # 如果该附件已经存课程中，则只更新附件创建时间
         mul_container.attachments.each do |att|
+          @exist = false
           if att.id == ori.id || (!att.copy_from.nil? && !ori.copy_from.nil? && att.copy_from == ori.copy_from) || att.copy_from == ori.id || att.id == ori.copy_from
             att.created_on = Time.now
             att.save