OSError: [Errno 28] No space left on device

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "electrum\gui\qt\settings_dialog.py", line 324, in on_exchange
  File "electrum\exchange_rate.py", line 652, in set_exchange
  File "electrum\simple_config.py", line 104, in _set_config_value
  File "electrum\simple_config.py", line 294, in set_key
  File "electrum\simple_config.py", line 304, in _set_key_in_user_config
  File "electrum\simple_config.py", line 416, in save_user_config
OSError: [Errno 28] No space left on device