On Windows 10 dagster/dagit 0.6.1, in the hello_dag example, the dagit pipeline execution finishes after only starting and finishing _solid_one_. This message is displayed in the logs:

An exception was thrown during execution that is likely a framework error, rather than an error in user code.
Original error message: OSError: [WinError 6] The handle is invalid

Stack Trace:
  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster_graphql\implementation\pipeline_execution_manager.py", line 312, in _in_mp_process
    instance,

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\execution\api.py", line 141, in execute_run_iterator
    step_keys_to_execute=step_keys_to_execute,

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\execution\api.py", line 101, in _pipeline_execution_iterator
    step_keys_to_execute=step_keys_to_execute,

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\engine\engine_inprocess.py", line 120, in execute
    yield step_event

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\contextlib.py", line 119, in __exit__
    next(self.gen)

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\execution\compute_logs.py", line 34, in mirror_step_io
    yield

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\contextlib.py", line 119, in __exit__
    next(self.gen)

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\execution\compute_logs.py", line 44, in mirror_stream
    yield

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\contextlib.py", line 119, in __exit__
    next(self.gen)

  File "c:\users\tnaugle\appdata\local\continuum\anaconda3\envs\dagster_new\lib\site-packages\dagster\core\execution\compute_logs.py", line 68, in redirect_stream
    from_stream.flush()

Thanks for the report! I believe we have a fix for this coming in 0.6.2 which we expect to release tomorrow

Thank you so much!

In the meantime, if you set the environment variable

PYTHONLEGACYWINDOWSSTDIO

to some non-empty string, I believe that will resolve the issue.