I've just downloaded and installed the Jatos Bundle (version 3.10.4) on Windows 11. All tests on my local instance are "OK", however creating a new study or importing any jzip from the Example Studies cause the following error: "Couldn't generate path to file or directory"

I would appreciate any help!

I created a lexical decision task in OpenSesame. However, whenever I try to share the link with participants, they receive the following message in their web browser: web page not available net::ERR_Connection_refused

Does anyone know hot to fix this issue?

Do I need to install JATOS on every participant's own laptop or computer?

Kind regards,

Yoran

I created an experiment using PsychoPy and adapted it for online use with JATOS. It was working normally until yesterday around 17:00 (GMT+2). Since then, when I try to run it, I get the following error message during loading:

“Unable to download resource: abcde_training_block - NOFEEDBACK.csv”

It also fails to download another resource file.

At the same time, my colleague, who created her experiment using OpenSesame and was also using JATOS without issues, is now experiencing a freeze with the message: “Building experiment structure.”

Could anyone help us understand what might be causing this issue?

Thank you very much!!

We have been running an online experiment using OSWeb v2.2.9 and JATOS mindprobe servers for a while now. Recently, we received reports from a few participants stating that the experiment freezes, crashes, or occasionally fails to display certain images. We launched the study after piloting, during which none of these issues occurred. We have already reached a sample size of 30, and only recently 2-3 participants reported such problems.

I was able to replicate the issues myself. Interestingly, different browsers behave differently. Chrome does not even allow the experiment to start, and the console throws the following error message: "Failed to load resource: the server responded with a status of 404 ()", specifically for the following image files: T_NC_toy%20car.jpg, T_NC_toy%20cell%20phone.jpg, T_NC_baby%20doll.jpg, and O_NC_pencil%20case.jpg.

Firefox allows the experiment to run initially, but then it freezes, I assume when one of the problematic images is about to be presented. Opera also allows the experiment to run, but the "broken" images are simply not displayed (we can tell because the text descriptions presented below the images still appear on those trials).

I have not included the experiment script, as I suspect the issue may be related to the JATOS server or OSWeb itself. However, I can share relevant parts of the script if necessary. We are not sure what we might be missing and would greatly appreciate any help or suggestions regarding this issue.

Thank you!

P.S.: Just noticed a recent discussion noting that the latest JATOS update is stricter with filenames so spaces are not allowed. I guess this explains everything.

Suddenly, I cannot access my study results on Mindprobe/JATOS. I was able to download the results on Friday, but now the Results page freezes completely.

When I open the Results page, the “Working...” window appears and the page freezes completely. I cannot click anything. Export also does not work. And that window never disappears. I've been waiting for so long on different browsers.

The browser console shows this error:

Uncaught RangeError: Invalid time value

  at Date.toISOString (<anonymous>)

  at getLocalTimeDataTables (2fae453d15a226314ed01950e7e5ff94-helpers.js:66:55)

  at Object._render (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:12162)

  at Object.fnGetData (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:14890)

  at G (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:19257)

  at Nt (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:31711)

  at s (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:26079)

  at a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:34084

  at Object.e [as success] (a7508584d686f953d98b51ddb380c2bb-datatables.min.js:16:30354)

  at c (2c872dbe60f4ba70fb85356113d8b35e-jquery-3.7.1.min.js:2:25304)

Is there a simple way to:

• export the data without opening the Results page, or
• remove the broken result?

I am not very familiar with JATOS technical details, so I would really appreciate simple instructions.

Study UUID: 9e0a6666-56b8-478e-86da-bc6a7cd9c113

Thank you very much.

I was encountering the same frozen results page problem, using Jatos through MindProbe, as reported in a previous discussion. But I accidentally deleted my study while I was trying to find a solution. Then when I imported again, I got this error message and the importing was not sucessful:

My jzip file is complete and workable as I used the same file and can sucessfully import it last time. I am wondering what should I do now? The error message seems a problem on the online server side which I don't have any access to visit. Any thoughts or suggestions are much appreciated. Thank you very much!

I am looking to use a joystick to collect responses for a go/no-go approach avoidance task. I see that it is possible using the built in gamepad feature in OpenSesame, however this component is not supported for use with JATOS. My question is whether I can use the JavaScript Gamepad API as a workaround, by including an inline script. Below is a link to more info on that API. Any ideas on whether this can work?

Thank you!!

I'm trying to use JATOS during my lab sessions where my students conduct experiments. I'm using JATOS 3.8.2 and Lab.JS, along with “General Multiple” links. There are about thirty 3KB images in the experiment.

The first time the students ran the experiment, I had no problems.

However, the second time (in the same room and on the same computers), the students started the experiment, but it froze very quickly and they were unable to continue. On the other hand, students using their own computers (who had not run the experiment the first time) were able to complete it.

Would you have any idea what the problem might be?

I'm trying to integrate my experiment on Jatos into Sona. I followed all the steps described here https://osdoc.cogsci.nl/4.1/manual/osweb/sonasystems/ except the last one, because I do not want to automatically grant the credits. I generated the study link and added "?SONA_ID=%SURVEY_ID%" at the end of the URL. The issues I'm getting are: batch session data is not getting the condition from "pending" and putting into "started" or "finished", so all participants did the default condition so far; I'm not getting the sona_participant_id (it's always -1). Apparently, there is something wrong with this integration.

This is my "sona" code on OpenSesame (version 3.3.11):

This is my "jatos_init_condition" code:

This is my "jatos_finish_condition" code:

This is how my experiment is configured on Jatos:

Example of how my Batch session data is structured:

I would really appreciate if you could help with that. I'm running out of time with this experiment.

Thanks in advance!

We're currently testing JATOS v3.9.8 rollout (in combination with OpenSesame 4.1.6), and noticed that the usual code for picking up query parameters is no longer working, e.g:

E.g. if (window.jatos && jatos.urlQueryParameters.SONA_ID) {
    console.log('Sona information is available')
    var sona_participant_id = jatos.urlQueryParameters.SONA_ID
} else {
    console.log('Sona information is not available (setting value to -1)')
    var sona_participant_id = -1
}

Specifically, window.jatos now returns -1, which obviously breaks the logic. I think I understand the reasoning from No data received on JATOS since update (on mindprobe) — Forum, and either window.jatos = jatos or checking for window.jatos_uuid instead could be a future solution. .

However rolling out with this change would impact many running experiments that would all need to be updated to prevent them from breaking. Has anyone else encountered this issue, and if so, found a good workaround?

Kind regards,

Kerwin

As it seems that it is not possible to manage the components directly from MindProbe, but only locally (to access the study assets folder), I installed JATOS Win Java on my PC and used the localhost9000 JATOS server. 

For now, I have created three fake tasks to test the components and check how they link to each other.

However, while component 1 jumps to component 2, component 2 never jumps to component 3. 

When muting task 2, however, it works well from task 1 to task 3 and the studies are displayed. This is not related to the tasks, as I also tested random task numbers; the problem lies with the serial position of 2 in the component order.

I followed the procedure indicated here: https://www.jatos.org/Combine-two-pre-written-studies-into-one.html and the changes in the html files here:

https://www.jatos.org/Write-your-own-Study-Basics-and-Beyond.html

I created the tasks in Opensesame and exported them as separate JZIP file. From the JATOS local GUI, I imported the studies separately to create three different studies, each with one component. 

This created three folders in my Jatos local folder. From my study assets folder, I copied and pasted:

1) only the HTML files for tasks 2–3, from their study asset folder, into the task 1 folder;

2) the full repertoire for both tasks into the task 1 folder. Neither of these worked, and sometimes studies 2–3 don’t even launch, staying on the 'OSWeb Loading studies' page.

and 3) I directly exported the html files from OpenSesame "Save as autonomous html file". On Jatos, this method worked better as the tasks could be run.

Is there an easy way for me to create this multi-component study ? 

I have been trying to make it work for days, and I even asked a colleague, but now I am stuck. 

Thank you very much for your help with this.

We are using JATOS for multiplayer experiments for quite some time now - and we absolutely love it!

In the past few days it seems that (perhaps because mindprobe has updated its JATOS to 3.9.8) we are experiencing a strange bug - where all our participants get a message saying "Study run is already finished", whereas JATOS status if failed for all of them and we get a message saying "Inactive group member was forced to leave its group". I am not sure how to read into this exactly, so any help would be appreciated!

best,

Isaac

1. It asks the participant to fill in a subject number, which should not happen.
2. It does not redirect the participant to Qualtrics at the end, but gets frozen on a black screen.

These problems do not occur in Firefox or Safari. I am up-to-date with the most recent versions of Chrome and OS Web. Below are screenshots of with the console log at the time it requests a subject number, and at the end of the experiment when it does not redirect to Qualtrics. Attached is the experiment file. Would welcome any suggestions for making the experiment run!

AB_Flow.osexp

10.65 KB

since the Mindprobe update to JATOS 3.9.8, participant data appears to no longer be transferred to or stored on the server. Participants are able to start and complete the study, but in the results "no data" is shown (see below). It also does not appear to be an isse for one specific study.

Is anyone else experiencing this problem and is there a quick fix?

Thanks!

I'm making my first ever OpenSesame experiment, and I'm pretty sure I haven't structured things as it's intended. Essentially, I have 12 studies on Mindprobe/JATOS that are all slightly different variants of the same experiment. I did this just to get 12 different links that I could give to people. Each of these 12 studies contain only one component, which is the entire experiment. When I run the studies from my view on Mindprobe, there's no problem. However, whenever I use a link (General Multiple) two things can happen:

1. If I have disabled "Allow reload" for my single component, the experiment freezes at the data transfer by the end of the run. On the result page it will say "It is not allowed to reload this component". Sometimes it shows errors in the browser console as well.
2. If I have enabled "Allow reload", the experiment finishes properly but the results get messy with several component results featuring duplicate data.

So far, I cannot understand what is causing these component reloads. I would of course like to avoid them. Again, I'm rather new to this and my effort has mostly gone to figuring out OpenSesame and OSWeb. I have likely misunderstood a lot about JATOS. Any help is appreciated.

Thanks!

We are going to conduct an online experiment using JATOS. However, it can only record 5M of data size, how can we extend this limit?

Thanks and best regards,

Lawliet

Of course, I can just set up a new experiment. No data has been lost. However, I think it would be important to figure out what happened here. Has anyone had similar experiences?

semi-frequently when I test run my components whether locally or on mindprobe it asks whether cookies are allowed in the browser (firefox) with an error in the console saying jatos cookies id 1, 2 or 6 are outdated, is this a local issue for me or is it likely to happen to other participants running the same experiment?

hopefully someone can help,

thank you,

Adrien

all my JATOS links of every experiment suddenly return 404 Not Found across all my studies and batches. Even Run → Preview inside JATOS results in 404. I didn’t change anything on my side (studies, batches, or components are Active).

Examples:

Full link (fails): https://jatos-server.web.rug.nl/publix/ycNvEauEVVE

Could you please help me with this? This is blocking live data collection...

Thank you!

Best

Runyu

I have tried to use the API for a recent study which requires frequent downloading of data and subsequent updating of study asset files. It works fine on the cortex test server.

When I tried it on mindprobe, I run into the problem that the server always returns a (the same) HTML file, regardless of which API endpoint I call. It seems to be the Login page (or redirect to one).

I found this to be a known problem with web servers, which redirect all requests to the Login page when a user is not logged in (probably checked via a cookie). Instead, calls to the API are authorized with the tokens, so there should be no redirect. Perhaps web server needs to be configured such that it does not redirect calls to URLs with "/api/" in it?

Is it me, or could it be a server issue?

Thank you for looking into it!

Christoph

However, now it looks as in the attached picture (even though the main study page does indicate we have 100+ results):

The reason why I noticed this is that I tried setting up a new study and was running into the same issue. Any help is much appreciated!

I have installed JATOS on my institutional server, and I can officially access it via web browser. It brings up a login page asking for username and password, as it expected from my experience on a local server. I can type in the boxes, but the buttons for sign in and such seem inactive, and the page is unresponsive. Anyone have any experience with this?

Thanks!

You're not allowed to access this resource.

I checked the server logs and found the following entries at the time of the export attempt:

2025-06-26 03:39:27,696 [INFO] - g.ErrorHandler - forbidden: No CSRF token found for application/json body  
2025-06-26 03:39:27,696 [WARN] - p.f.CSRF - [CSRF] Check failed because application/json for request /jatos/api/v1/results?isApiCall=false

This suggests a CSRF check failure when attempting to retrieve the result data via the API. Could you please let me know if this is a known issue in version 3.9.6, and if there is a way to fix or work around it?

Thank you for your assistance.

Best regards,

As many of you, including me, are in love with JATOS and its capabilities, one main concern for me is always the distance of observer from screen (specifically, I am a vision researcher and this is important specifically in visual search tasks and related), so I have developed a plugin which uses a camera to speculate the distance of user from camera.

I have uploaded it on mindprobe for test, and it will be way beyond your kindness if you test it (it takes less than a minute) and share your feedback with me. It is important I have different measures before moving forward to understand if it is working closely to reality and has enough accuracy.

If so, please visit this short link https://tinyurl.com/jscamdist or directly https://jatos.mindprobe.eu/publix/1E182KYedqu and test it. All essential information is there and explained well.

It would be amazing if you could also measure distance, or if you already know, provide it so we can calculate % of accuracy and get a better view if there is any problem with plugin and measuring. All details will be submitted via form embedded in the address.

Thank you for your collaboration!

If you want WMIC, you can install it through optional features or the command prompt (as administrator). However, if you, like me, want to avoid potential conflicts with WSL (Windows Subsystem for Linux), I've modified the bat file to work without WMIC. Simply replace the existing loader.bat file with my modified version and run it. No other changes are needed; I've reconfigured the script to use Windows Terminal integration instead of WMIC.

you can open it via text editor and replace it with current .bat loader.

I’m currently running a jsPsych experiment on JATOS. I’ve enabled the “Allow reload” option in my study, but I noticed that when a participant closes the page and reopens it (using the same link), the experiment always starts from the beginning, rather than resuming from where they left off.

Is there any way to allow participants to continue from their last position in the timeline when reloading the study?

Thank you in advance for your help!

Best regards,

Runyu

One of My participants told me she can listen to the audio on the page where there is only 4 audio clips, but on the page where there is 20, the audios can't be played...Strangely, some of my participants said they do not have such problems, me neither..

The console showed: AbortError: The play() request was interrupted by a call to pause().

the original javascript is: var stimuli1 = [

'my_audio/Australia1.mp3',

'my_audio/glasgow1.mp3',

'my_audio/India1.mp3',

'my_audio/Ireland1.mp3',

'my_audio/Japan1.mp3',

'my_audio/Manchester1.mp3',

'my_audio/Mandarin1.mp3',

'my_audio/Northern Ireland1.mp3',

'my_audio/NZE1.mp3',

'my_audio/South Africa1.mp3',

'my_audio/Australia2.mp3',

'my_audio/glasgow2.mp3',

'my_audio/India2.mp3',

'my_audio/Ireland2.mp3',

'my_audio/Japan2.mp3',

'my_audio/Manchester2.mp3',

'my_audio/Mandarin2.mp3',

'my_audio/Northern Ireland2.mp3',

'my_audio/NZE2.mp3',

'my_audio/South Africa2.mp3'

];

var preload = {

type: jsPsychPreload,

auto_preload: true

};

var cluster_trial_1 = {

type: jsPsychAudioTokens,

ratingtype: 'cluster',

stimuli: stimuli1,

force_listen: false,

loop: true,

prompt: `

<div style="font-size:14px; line-height:1.0; margin-top:30px;">

<p>您觉得哪些口音听起来比较像？请将这些音频按照相似程度拖拽分组。拖拽时圆点之间出现连线，才会被视为一组。</p>

<p>音频无法播放? <strong>请耐心等待30秒。</strong></p>

</div>

`

};

Could you please tell me why this is happening and help me how to change / improve my code?

Thank you so much!

Best

Runyu

You're not allowed to access this resource.

even though JATOS GUI shows notification that the file was downloaded successfully. Looking at JATOS application log, there's a reference to CSRF token which seems to refer to some cross-site scripting security feature:

2025-07-08 11:40:42,964 [INFO] - g.ErrorHandler - forbidden: No CSRF token found for application/json body
2025-07-08 11:40:42,964 [WARN] - p.f.CSRF - [CSRF] Check failed because application/json for request /jatos/api/v1/results/data?asPlainText=true&isApiCall=false
2025-07-08 11:40:33,792 [INFO] - gui_access - GET /jatos/componentResults/tableData?componentId=115&_=1751964033695 (admin)
2025-07-08 11:40:33,627 [INFO] - gui_access - GET /jatos/57/115/results (admin)
2025-07-08 11:40:32,104 [INFO] - gui_access - GET /jatos/57/componentsTableData?_=1751964032023 (admin)

I'm assuming this is related to JATOS 3.9.3 CSRF vulnerability https://nvd.nist.gov/vuln/detail/CVE-2024-51382 . I already tried out creating a new user (instead of admin) and using that to download the results file, but end up with the same broken results file output. Spending some time in JATOS github repo (with CSRF search terms) I ended up with a workaround of adding these to jatos.conf effectively removing these CSRF features completely (I would assume) but I feel it's a bit hacky..

play.filters {
 enabled -= play.filters.csrf.CSRFFilter
}

Should this be documented somewhere more clearly? I'm fine with this workaround, but somehow feel it should be default config for new users.

Im trying to import the study in a jzip format from my local JATOS server to the university JATOS server. The jzip is just 14.6MB but it failed showing "413 request entity too large'...

So is it too large? is it some ways to solve this problem since it cannot be reduced in size..

Thank you very much for your help!

Best

Runyu

First, I want to say thanks for developing such a terrific program for research. It is such a valuable and appreciated contribution to science.

The problem I am having:

When I am running my study online I am getting a consistent error when submitting results and moving from the first component of a study to another. This error only occurs when the study is moved online, it does not occur locally. Otherwise, the study is stable.

When this error occurs, the study breaks and does not continue to the subsequent 2 components. Data is not collected for the finished first component.

My study has three components. When I complete the first component and the study results are due to be uploaded to the JATOS webserver, I receive an error message when moving to the next component, with a "Study run already finished" error, citing the study run as complete.

I have attached an image of the console log.

A little bit of information:

I am running Firefox 140.0.2 (64-bit) Windows.

Jatos version v3.9.5

JsPsych v8

I am recruiting participants through Prolific, so am using the "General Multiple" study link.

What I have tried, and seemed to work:

In JATOS, when I enable "allow reload" for each separate component in the study this seems to resolve the problem (maybe in submitting the results the study component reloads, before moving on?).

Is this an appropriate way to deal with this error? Or is there a safer option?

A related question—is there a way to load/stress test the study with windows?

Thank you again for all of your support and building and maintaining such a terrific program, it is greatly appreciated.

Best,

Jesse