Unfortunately we encountered the following error: - when uploading participant's results

URL of experiment:

Description of the problem: Need help from Pavlovia team. This study ran fine 11 times (11 credits consumed) while me and my students were testing it pre-launch. With the very first real participant, we were informed of an error that occurred at the end of the experiment. She sent a screenshot so I know it is legit.

"unfortunately we encountered the following error:

  • when uploading participant’s results for:

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

It takes ~45 minutes to run this experiment and this is a terrible error for a participant to receive. I see the CSV file in the repository, but no log file. Can someone please advise?

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Hello @trincoll,

I believe you are referring to this particular .csv file: PARTICIPANT_testScript_2020-10-19_18h20.42.980.csv
There was indeed a rather odd error, possibly triggered by an interruption of the connection between the participant’s browser and pavlovia.org at a rather crucial moment.
Luckily the data was saved on this occasion, and your credit was not consumed. But indeed the logs could not be uploaded since the participant’s experiment was interrupted by the error. And it is not pleasant an error message to receive for a participant, of course.

I am looking into how to prevent the situation from occurring again.


Thanks for getting back to me so quickly @apitiot . Yes, that it the session that I was referencing.

I had someone run it again from start to finish and that session went fine. Is it likely that this error will continue to occur?

It is my understanding that this was only a partial result. Can you confirm that the experiment was indeed interrupted before it finished? And if so, do you think the participant closed the tab or is that the case that there is a button somewhere that gives participants the possibility to interrupt the experiment?


See screenshot for actual error. This was sent via text to the student who sent the participant the link.

In the datafile, all of the trials are recorded. It must have happened right after the last trial of the last part. But it did not redirect to our Qualitrix URL, which is the last step.

I don’t think they closed the tab as they were able to screenshot this error. Also, I don’t think they can interrupt the study (apart from hitting the escape key which would end the study and generate a different kind of message, at least that’s what happens during piloting).

Two people have completed it since this error with no problem. Is it OK to continue the study? Is this likely to recur?

@apitiot Just following up here. We had another participant reach out and say the exact same thing happened to them. The approximate time was Wednesday, Nov 4th, sometime in the morning EST. Can you verify that this happened again and is there a way to know why?