File "electrum\gui\qt\main_window.py", line 3237, in closeEvent
  File "electrum\gui\qt\main_window.py", line 3258, in clean_up
  File "electrum\gui\qt\__init__.py", line 307, in close_window
  File "electrum\daemon.py", line 286, in stop_wallet
  File "electrum\address_synchronizer.py", line 169, in stop_threads
  File "electrum\util.py", line 356, in <lambda>
  File "electrum\util.py", line 352, in do_profile
  File "electrum\storage.py", line 88, in write
  File "electrum\storage.py", line 99, in _write