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 452, in on_currency
  File "electrum/exchange_rate.py", line 543, in set_enabled
  File "electrum/simple_config.py", line 170, in set_key
  File "electrum/simple_config.py", line 179, in _set_key_in_user_config
  File "electrum/simple_config.py", line 272, in save_user_config
OSError: [Errno 28] No space left on device