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\main_window.py", line 720, in <lambda>
  File "electrum\gui\qt\main_window.py", line 341, in toggle_tab
  File "electrum\simple_config.py", line 171, in set_key
  File "electrum\simple_config.py", line 180, in _set_key_in_user_config
  File "electrum\simple_config.py", line 273, in save_user_config
OSError: [Errno 28] No space left on device