Internal Error - Only the background screen is displayed

OS (e.g. Win10):
PsychoPy version: 2020.2.4.
Standard Standalone? (y/n) yes


Dear Community,

when I try to start an experiment in the runner (which was previously built in the builder), only the background is displayed - regardless of the experiment, which is why I suspect that it is not the code. After all, the window can only be closed using the Task Manager. Below the error.

Many thanks for your help!

What did you try to make it work?: I uninstalled PsychoPy and reinstalled it.

What specifically went wrong when you tried that?:

Traceback (most recent call last):
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 274, in onClose
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 282, in onQuit
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 541, in stopTask
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 107, in stopFile
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 510, in onProcessEnded
  File "C:\Program Files\PsychoPy3\lib\site-packages\psychopy\app\runner\", line 133, in onProcessEnded
AttributeError: 'NoneType' object has no attribute 'stdOut'

In addition: Running a demo directly in the coder works. Maybe it has something to do with the Experiment Runner?

PS: The starting page of the experiment was finally displayed. But it took a few minutes and afterwards the error in the starting post of this thread was displayed.

This is a known bug - if you close Runner or if you have your preferences set up so that only the Builder or Coder window opens on launch, then the app’s internal representation of Runner is just None and so any attempt to send things to the output window causes this error. To fix, just set your preferences to open Builder, Coder and Runner on launch and try to avoid closing the Runner.

2020.2.5 will be out soon and will have this issue fixed!

1 Like

Dear AlexanderLe and TParsons,
I experience the same problem and I got the same error when runningthe version 2020.2.5
I am tryingto run a simple experiment made with a 10 seconds text, but I got exactly the same error. The screen freezes and I have to restart the PC

I have Win10, standalone version of Psychopy 2020.2.5 64bit

Any suggestion to solve this issue? Many many thanks in advance!

I’m not sure what was causal in solving the problem. But after I reinstalled Psychopy, updated my graphics driver, installed all Windows updates and cleaned my system, it worked again. Maybe this will help you.
Best regards!

thanks a lot for the feedback! I proceeded in the way described here, and it seems I have solved this issue…