Error when removing "participant" field from experiment settings


I would like to get rid of the first window with “participant” field and “downloading resources” field when starting the online experiment. No luck so far. Interestingly, if I try to get rid of the participant field, I get the following error and I then need to quit Psychopy.

Traceback (most recent call last):
File “/Applications/”, line 1139, in setExperimentSettings
File “/Applications/”, line 1833, in init
File “/Applications/”, line 515, in init
File “/Applications/”, line 629, in addCategoryOfParams
File “/Applications/”, line 756, in addParam
File “/Applications/”, line 132, in init
File “/Applications/”, line 542, in init
AttributeError: The initial value for a ListWidget must be a list of dicts

Any idea?

This is a known bug which will be fixed in 2020.2.5, as a temporary fix you can open the .psyexp file in a text editor (e.g. Notepad) and replace the following line:

<Param name="Experiment info" updates="None" val="" valType="code"/>


<Param name="Experiment info" updates="None" val="{'participant':'', 'session':'001'}" valType="code"/>