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Issue with piloting an online experiment

I am having some issues piloting an online experiment on Pavlovia and was wondering if someone might be able to help.

The experiment will not generate an URL, but the title is, “Emotional Awareness” (private mode) and username is: arkadiym

Description of the problem: I recently uploaded my experiment from PsychoPy to Pavlovia, and am having issues pyloting the study. I am getting the following error when I click the “Pilot” button:

"We could not find a record for experiment designer: undefined

Please check the name and try again. If the error persists, contact Pavlovia’s administrator."

In case this is helpful, I got the following error, when changing the status of the experiment to “Pilot”.

1 Like

The JavaScript file was never created for your study. When you exported/synced the study online were there any error messages?

Hi Jon,

Thank you for the quick response.

I did not get any error messages when I uploaded the study the first time. But given that you pointed this out, I deleted the old project and tried to export it again. I did not get any error messages when exporting (screenshot attached of the printout) but I am getting the same message as earlier when I try to convert the project to the Pilot phase (screenshot attached).

I did notice that after the project was exported my browser loaded some webpage which said “404 Not Found”. Screenshot attached of this as well.

Let me know if you might have any suggestions. Thank you for all your help with this!



My apologies, the system is not letting me add too many screenshots at once, since I am a new user. I am just including the text of the PsychoPy printout here, which was generated after pushing the data:

“Pushing files to Pavlovia
Pushing to Pavlovia for the first time…
Branch ‘master’ set up to track remote branch ‘master’ from ‘’.

And also attaching the error that gets generated when trying to convert the experiment to Pilot mode:

In case this is helpful, I tried creating an experiment which displays, “Hello World” and it successfully pushed to Pavlovia and ran in Pilot format without issues.

I have done a little more troubleshooting and discovered the following:

  1. When I upload an experiment with text only, there are no issues.

  2. When I upload an experiment with an image, there is a problem. In this case, I created a small experiment which only displays text and one picture, then terminated at the press of a button. The experiment is called testing_project with the Project ID: 12336. This started generating an error message (screenshot attached when I tried to run it on Pavlovia. I did check and the PNG image was uploaded successfully.

Not sure if this extra information helps with the troubleshooting, but sharing in case it does.

Thank you for all your help with this,


1 Like

@jon After some testing, I narrowed down the problem to syncing issues using the rating scale. I am now changing my experiment to use the slider instead, but the slider marker size changes after syncing Psychopy with Pavlovia. Wondering if you might know how that can be adjusted in Javascript?

Hello @arkadiy,

The issue you are experiencing has to do with the testing_project experiment being in PILOTING mode. Consequently, in order for you to run it, you need to go to your dashboard and press the pilot button.
Let me know how that goes!


Hi Allan,
Thank you for the suggestion.
Unfortunately, that error persists, when I run the project as you suggested. That is how I initially tested it. I think I narrowed down the problem to two issues: the rating scale (replaced with the slider) and the fixation cross (replaced with blank screens). Neither one of those seem to work in Pavlovia.

Hi @arkadiy,
I’m having the same issue. Did you find a solution in the end? My slider buttons are fine locally but huge in Pavlovia. Units are set to “height” for the slider and in Experiment settings. Thanks!

Hi @lcrible,
Yes- I did find a solution.

The following worked for me:

  1. Add a code module to the Psychopy routine.
  2. Open the code module, and select “Both” on top in the code window, this will allow you to edit Python on the left, and Javascript on the right.
  3. Click on the “Begin Experiment” tab, and enter the following code (modify the parameters to fit your experimental needs):
// Begin Experiment
col = new util.Color('black')  // Create your color once
newMarkerSize = 50  // in pixels`Preformatted text`
  1. Click on the “Each frame” tab and enter the following code:
// Each Frame
try {
    if ( !== {
        Slider2._markerColor = col;
        Slider2._marker.lineStyle(1,, 1, 0.5);
        Slider2._marker.beginFill(, 1);
        Slider2._marker.drawCircle(0, 0, newMarkerSize / 2);
        Slider2._needUpdate = true;
} catch (err) {}

Note: You will need to modify the above code to fit the name of your slider (mine was called “Slider2”, but you should change yours according to the name of your slider. Make sure to leave the formatting of the code (i.e. the “.” after the slider name).

  1. If this works, do a little trial-and-error to modify the size (and color, if needed) on the “Begin Experiment” tab to get them to the desired size.

Let me know if this works,