title: AWS CLI - All commands return Unknown output type: [None]
body: <p>All of my aws-cli commands returned </p>
  
  <blockquote>
    <p>Unknown output type: [None]</p>
  </blockquote>
  
  <p>I checked my configuration</p>
  
  <blockquote>
    <p>$ aws configure</p>
  </blockquote>
  
  <p>appeared normal but i was unable to edit my 'Default output format'</p>
  
  <p>I ran my aws-cli command with --debug and saw</p>
  
  <pre><code>MainThread - awscli.clidriver - DEBUG - Exception caught in main()
  Traceback (most recent call last):
    File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 208, in main
      return command_table[parsed_args.command](remaining, parsed_args)
    File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 345, in __call__
      return command_table[parsed_args.operation](remaining, parsed_globals)
    File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 517, in __call__
      call_parameters, parsed_globals)
    File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 638, in invoke
      self._display_response(operation_name, response, parsed_globals)
    File "/Library/Python/2.7/site-packages/awscli/clidriver.py", line 657, in _display_response
      formatter = get_formatter(output, parsed_globals)
    File "/Library/Python/2.7/site-packages/awscli/formatter.py", line 272, in get_formatter
      raise ValueError("Unknown output type: %s" % format_type)
  ValueError: Unknown output type: [None]
  </code></pre>