Online experiment error message: unable to download resource


My experiment runs perfectly well on psychopy offline, but I keep having some error messages when I run it online on Pavlovia
Here is a link to my experiment: SetA_songs [PsychoPy]

It cannot load one of my conditions file (xlsx) or one of my sound files.
error1 error2
Participants will hear a song and for each song, they will provide ratings (I used slider properties to set this up)

Can anybody help me with this? Thank you!!

Hi, did you end up finding a solution to this?

Yes, I’m getting the exact same error…

Hi Psychopy team,
this error occurs to our experiment too - mostly for stimulus_condition.csv file which is puzzling as the file size is not really big. And sometimes successful, and sometimes not.
If any tips illuminating the issues we’d appreciate it.

Hi, in my experiment, we finally realized that loading all those audio files(over 100) in .wav format was too heavy. When we converted them to .mp3, we stopped having problems. You can also try clearing cache before starting the experiment.
Also, while trying out a variant of this experiment using embedded loops only (excel conditions file pointing to other excel conditions files), we noticed that pavlovia doesn’t download all the appropriate excel files for some reason.
And the last potential problem source is that not all your resources are in the html resource folder. If that is the case, you can just copy the missing files to that folder. This can happen when using code to select file name instead of using excel sheets.

I hope this helps!

I am getting this same error message when trying to run my experiment, which contains 120 jpg images. I am not sure how to fix this problem, as the experiment runs correctly on PsychoPy but has this error when I try to run it on Pavlovia. If anyone knows any solutions it would be great as I have tried the other solutions already stated above.


Unfortunately we encountered the following error:

  • when downloading the resources for experiment: Emotional Memory Task
  • unable to download resource: Images/121.jpg (FILE_LOAD_ERROR)

Try to run the experiment again. If the error persists, contact the experiment designer.


Is your folder online Images with a capital I?


I had the same problem, and in fact I had to check in all my images if their extension was jpg or JPG, in builder it doesn’t matter, but in js I guess it does. So if the original is jpg, you have to have jpg, if the original file is JPG than put in capital letters. I did this in my experiment and the problem was solved.