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\my_treeview.py", line 101, in <lambda>
  File "electrum\gui\qt\my_treeview.py", line 110, in _do_toggle_config
  File "electrum\simple_config.py", line 145, in set
  File "electrum\simple_config.py", line 111, in _set_config_value
  File "electrum\simple_config.py", line 304, in set_key
  File "electrum\simple_config.py", line 314, in _set_key_in_user_config
  File "electrum\simple_config.py", line 426, in save_user_config
OSError: [Errno 28] No space left on device