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Error in uploading participant's results - Data loss

URL of experiment:

Description of the problem:
Hello everyone!
I just started running my experiment, and I am currently dealing with a very big problem. 2 of my participants’s data was not found, even though they said that they completed the study. one of them said that her internet connection crashed at the end of the experiment. I checked myself what happens when internet connection is not working. I discovered that if the connection crashed at the middle of the experiment, but than it was fixed before the end, the data file uploaded properly to pavlovia. But, if internet connection crashed at the end, the data file could not be uploaded to the server, and this massage appears:

Unfortunately we encountered the following error:

  • when uploading participant’s results for experiment [experiment name]

This is a big issue for me because I run a longitudinal study and every data loss is loosing a very hard work.

PLEASE tell me there is any way of fixing it! I know that even if the internet is not connected while experiment is running, results are still being saved, and they can be lost only at the server uploading step. So, maybe is there another way reaching results? maybe through participants computer?

Thank you in advance!!


Hi Neta,

Sorry to hear you are experiencing this.

Firstly, can I please check that you have the “save incomplete results” option selected. As below,

Annotation 2020-09-03 094103


Hello Becca!

Yes, I have the “save incomplete results” option, and it is working, only when the internet is connected.

I had the save issue a few days ago. Participant informed me that they received an “upload error and if it persisted to contact the administrator.”. This only happened with one person, and I got one of their sessions (follow up session), but not the initial session. I was wondering if there might be a way to retrieve the data?

Sadly, I didn’t find any solution for this problem :frowning:
At first I found that if participants connects their computers to the internet before they are closing experiment tab it will save the data.
But I just found out it doesn’t work for all participants.
I think Pavlovia’s team should resolve this… they need to write a code which command to download data file in case there is no internet connection.

@Neta_Weitzman and @arkadiy, did you find out what was going wrong with your studies? I am facing the same problem, though I did not have “save incomplete results” checked. Are you accepting text input from participants? I am and was wondering if a “bad” character messed up some data files.

If there isn’t a way to retrieve the data, have you since found a solution so that this does not happen again?

Hi all,
Bumping this; I have had this happen several times as well; for ~250 participants collected it has happened maybe 5 times. It surprises me that these (supposedly complete) data files are completely missing even though I have partial data from other participants who have only passed through a couple of screens.

Hi There,

I wanted to highlight that another possible reason here is if your participant closes the whole browser before the green ‘thank-you’ message is presented (i.e. between the orange please wait and green notification boxes).

with 5/250 occasions I think it is possible this could have happened.

Ensure to emphasise to participants that they must wait until they see the green thankyou box :slight_smile:

1 Like

Hi @Becca, thanks for the idea. I think my case might be something different-- the participants say they received an error message, which I don’t think would happen if they just closed the browser. Maybe they just closed a tab? Unfortunately, none of them could remember the error, which makes it hard to troubleshoot.

I still find it strange that I wouldn’t even have partial data for these, even though I do have it for other cases.

I’m also having this issue which resulted in the loss of multiple participants’ data, has anyone found a solution to this problem? Participants say they get a message that says ‘an error occurred when uploading the result’. Because the issue only appears sometimes, it’s really difficult to replicate locally.

I also don’t have any partial data saved for these data even though I have save-incomplete on.

I am also having this issue where some participants randomly get error message when their data is uploading. Some of them completely miss all files while others just miss log files.

Is there a way to save multiple data files per participant to ensure that the internet does not crash at exact wrong moment? @Becca

This is the error a participant got which lost their data at the end:

the following error is encountered after completing the study:
Unfortunately we encountered the following error:

  • when flushing participant’s logs for experiment: lewis-lab/monsters_zapping_game_study1a
  • when uploading participant’s log for experiment: lewis-lab/monsters_zapping_game_study1a
  • when saving logs from a previously opened session on the server
  • unable to push logs file: 199_monsters_pilot_2021-02-15_18h15.23.546.log to GitLab repository: Cmd(‘git’)failed due to: exit code(128) cmdline: git commit --author=Pavolovia Commiter -m data: …

Hi There,

Sorry you are experiencing this! As far as I know it is not possible at the moment to save multiple datafiles to pavlovia. Thanks for logging the exact error message here though this will allow us to investigate.


great, thank you!

@Becca I received a separate error too on another participant who finished the study but upon uploading, they received the following:


Unfortunately we encountered the following error:

  • When uploading participant’s results for the experiment:
  • when saving data from a previously opened session on the server
  • either the credit reserved for this session has been released or no credit was previously reserved: results cannot be saved

I hope my sharing of these is helpful for you.

I am also facing the same issue. My participants finished the experiment but while saving the results an error message appeared. I am attaching the error message. The credit is still in reserve. Can we do something to retrievd the data before the credit is released.
Any help will be appreciated

Thank you

Sorry,I forgot to attach the file. Here it is

I got the same result today with a participant. Any update on this error?

I also just got the same problem.