diff --git a/addons/project/project.py b/addons/project/project.py
index f6c8c1ef4b2..c28bb84f876 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -257,7 +257,8 @@ class project(osv.osv):
         res = super(project, self).copy(cr, uid, id, default, context)
         for follower in proj.message_follower_ids:
             self.message_subscribe(cr, uid, res, partner_ids=[follower.partner_id.id], subtype_ids=[subtype.id for subtype in follower.subtype_ids])
-        self.map_tasks(cr, uid, id, res, context=context)
+        if 'tasks' not in default:
+            self.map_tasks(cr, uid, id, res, context=context)
         return res
 
     def duplicate_template(self, cr, uid, ids, context=None):