diff --git a/addons/account/account_move_line.py b/addons/account/account_move_line.py
index a7fd2adf33e..bdc1941238d 100644
--- a/addons/account/account_move_line.py
+++ b/addons/account/account_move_line.py
@@ -1030,6 +1030,8 @@ class account_move_line(osv.osv):
         all_moves = list(set(all_moves) - set(move_ids))
         if unlink_ids:
             if opening_reconciliation:
+                raise osv.except_osv(_('Warning!'),
+                    _('Opening Entries have already been generated.  Please run "Cancel Closing Entries" wizard to cancel those entries and then run this wizard.'))
                 obj_move_rec.write(cr, uid, unlink_ids, {'opening_reconciliation': False})
             obj_move_rec.unlink(cr, uid, unlink_ids)
             if len(all_moves) >= 2: