Traceback (most recent call last):
  File "electrum\gui\qt\main_window.py", line 2506, in closeEvent
  File "electrum\gui\qt\main_window.py", line 2537, in clean_up
  File "electrum\gui\qt\__init__.py", line 483, in close_window
  File "electrum\daemon.py", line 546, in stop_wallet
  File "concurrent\futures\_base.py", line 458, in result
  File "concurrent\futures\_base.py", line 403, in __get_result
  File "electrum\daemon.py", line 555, in _stop_wallet
  File "electrum\wallet.py", line 547, in stop
  File "electrum\wallet.py", line 482, in save_db
  File "electrum\json_db.py", line 48, in wrapper
  File "electrum\json_db.py", line 389, in write
  File "electrum\json_db.py", line 48, in wrapper
  File "electrum\json_db.py", line 400, in _append_pending_changes
  File "electrum\storage.py", line 112, in append
MemoryError