# Latest **URL:** https://psychtoolbox.discourse.group/latest.md [Latest](https://psychtoolbox.discourse.group/latest.md) · [Categories](https://psychtoolbox.discourse.group/categories.md) · [Tags](https://psychtoolbox.discourse.group/tags.md) --- ## [Action needed to save PsychToolbox](https://psychtoolbox.discourse.group/t/action-needed-to-save-psychtoolbox/5674)
**Author:** [@dcnieho](https://psychtoolbox.discourse.group/u/dcnieho)\ **Replies:** 0\ **Last updated:** [March 31, 2025, 5:10am UTC](https://psychtoolbox.discourse.group/t/action-needed-to-save-psychtoolbox/5674 "2025-03-31T05:10:29Z")
Dear colleague, PsychToolbox (PTB) was first released 30 years ago this year and remains one of the most widely used software packages for running behavioural experiments. It offers unrivalled cross-platform visual and … --- ## [Psychtoolbox Demos / Tutorials](https://psychtoolbox.discourse.group/t/psychtoolbox-demos-tutorials/4012)
**Author:** [@pscarfe](https://psychtoolbox.discourse.group/u/pscarfe)\ **Replies:** 36\ **Last updated:** [August 6, 2025, 2:42am UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-demos-tutorials/4012 "2025-08-06T02:42:18Z")
Hi all. A while back I wrote a bunch of demos for PTB. These seemed to prove useful to folk, but thanks to Adobe I was for a long time not able to update my website. I also got a lectureship, so my time for doing coding… --- ## [Posting guidelines](https://psychtoolbox.discourse.group/t/posting-guidelines/3058)
**Author:** [@Ian-Max-Andolina](https://psychtoolbox.discourse.group/u/Ian-Max-Andolina)\ **Replies:** 0\ **Last updated:** [February 18, 2020, 2:19am UTC](https://psychtoolbox.discourse.group/t/posting-guidelines/3058 "2020-02-18T02:19:39Z")
These are user-led forums (and most of us are busy doing our own research), so if you wish to stand the highest chance of getting a useful reply, please make sure you try to craft a clear descriptive post. If you are ne… --- ## [Experimental direct OpenGL-to-Metal presentation backend for Psychtoolbox on Apple Silicon](https://psychtoolbox.discourse.group/t/experimental-direct-opengl-to-metal-presentation-backend-for-psychtoolbox-on-apple-silicon/5811)
**Author:** [@keith](https://psychtoolbox.discourse.group/u/keith)\ **Replies:** 11\ **Last updated:** [September 21, 2026, 7:15pm UTC](https://psychtoolbox.discourse.group/t/experimental-direct-opengl-to-metal-presentation-backend-for-psychtoolbox-on-apple-silicon/5811 "2026-09-21T19:15:24Z")
Motivation I have been investigating the presentation-timing problems affecting Psychtoolbox on Apple Silicon under recent macOS versions. In particular, ordinary drawing and unscheduled flips can appear to work, while s… --- ## [Visual synchronization error using an AMD Radeon RX 9070 XT card with Ubuntu 24.04 LTS](https://psychtoolbox.discourse.group/t/visual-synchronization-error-using-an-amd-radeon-rx-9070-xt-card-with-ubuntu-24-04-lts/5812)
**Author:** [@till\_schneider](https://psychtoolbox.discourse.group/u/till_schneider)\ **Replies:** 3\ **Last updated:** [September 19, 2026, 3:02am UTC](https://psychtoolbox.discourse.group/t/visual-synchronization-error-using-an-amd-radeon-rx-9070-xt-card-with-ubuntu-24-04-lts/5812 "2026-09-19T03:02:09Z")
Dear PTB Team, We have the latest licensed PTB Version (3.0.22.3) installed on Ubuntu 24.04.4 LTS with Matlab 2025b. The CPU is a AMD Ryzen 9 9950X x 32 and the graphics card is a AMD Radeon RX 9070 XT. Nevertheless, … --- ## [VR Eye tracking](https://psychtoolbox.discourse.group/t/vr-eye-tracking/5757)
**Author:** [@pscarfe](https://psychtoolbox.discourse.group/u/pscarfe)\ **Replies:** 6\ **Last updated:** [September 9, 2026, 3:59pm UTC](https://psychtoolbox.discourse.group/t/vr-eye-tracking/5757 "2026-09-09T15:59:51Z")
Dear all, I would like to purchase a VR HMD with eye tracking that works with Psychtoolbox. From the following link with update notes it looks like eye tracking is supported in PTB via OpenXR. http://psychtoolbox.org/… --- ## [Psychtoolbox 3.0.22.3 "The most fantastic Matala" 🍹](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-3-the-most-fantastic-matala/5810)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [August 14, 2026, 3:16pm UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-3-the-most-fantastic-matala/5810 "2026-08-14T15:16:01Z")
Psychtoolbox 3.0.22.3 “The most fantastic Matala” was released on 14th August 2026. … A last act of work from a greek island before it is :beach\_with\_umbrella: time, so the brain can calm down and go into full vacation … --- ## [Subscription Model Q&A](https://psychtoolbox.discourse.group/t/subscription-model-q-a/5678)
**Author:** [@pscarfe](https://psychtoolbox.discourse.group/u/pscarfe)\ **Replies:** 31\ **Last updated:** [August 1, 2026, 6:27pm UTC](https://psychtoolbox.discourse.group/t/subscription-model-q-a/5678 "2026-08-01T18:27:44Z")
Dear all, As you will have seen, PTB is moving over to a subscription model for macOS and Windows for the 3.0.20 release onwards. Details can be found at the following links: https://psychtoolbox.discourse.group/t/act… --- ## [License activation](https://psychtoolbox.discourse.group/t/license-activation/5809)
**Author:** [@BlueStickyNote](https://psychtoolbox.discourse.group/u/BlueStickyNote)\ **Replies:** 1\ **Last updated:** [July 13, 2026, 9:15pm UTC](https://psychtoolbox.discourse.group/t/license-activation/5809 "2026-07-13T21:15:47Z")
Hi, I have a license key from August 2025. I have received a new laptop and installed the Psychtoolbox version 3.0.22. How do I activate the toolbox with the license key ? Authentication token : 67778-IL-202671013364:b… --- ## [On vacation until early September 2026 ☀](https://psychtoolbox.discourse.group/t/on-vacation-until-early-september-2026/5807)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [June 15, 2026, 4:23am UTC](https://psychtoolbox.discourse.group/t/on-vacation-until-early-september-2026/5807 "2026-06-15T04:23:06Z")
While my last “vacation” was mostly working twice as hard, and wasting away employer mandated vacation days from last year, this time it will be a real vacation in a sunny country with beaches :beach\_with\_umbrella:, sea … --- ## [Not using pageflips on recent AMD RDNA 4 gpu's on Ubuntu 24.04, Debian 13](https://psychtoolbox.discourse.group/t/not-using-pageflips-on-recent-amd-rdna-4-gpus-on-ubuntu-24-04-debian-13/5806)
**Author:** [@uwtuebingen](https://psychtoolbox.discourse.group/u/uwtuebingen)\ **Replies:** 6\ **Last updated:** [June 11, 2026, 6:16pm UTC](https://psychtoolbox.discourse.group/t/not-using-pageflips-on-recent-amd-rdna-4-gpus-on-ubuntu-24-04-debian-13/5806 "2026-06-11T18:16:34Z")
Disclaimer Yes, I am willing to contribute by testing with the new hardware. Yes, I am willing to use the payed support if needed. We do have payed licenses. Describe the bug New computer with new GPU “Navi RX 9060 … --- ## [Screen GetImage](https://psychtoolbox.discourse.group/t/screen-getimage/5805)
**Author:** [@pscarfe](https://psychtoolbox.discourse.group/u/pscarfe)\ **Replies:** 2\ **Last updated:** [May 19, 2026, 8:37pm UTC](https://psychtoolbox.discourse.group/t/screen-getimage/5805 "2026-05-19T20:37:00Z")
I am not sure if this is expected behaviour, but on macOS Screen(‘GetImage’, window) Gives the Psychtoolbox startup window with the frog, regardless of what is on the screen. Specifying the back or draw buffer results … --- ## [Quick fix for Mac Tahoe timing issues](https://psychtoolbox.discourse.group/t/quick-fix-for-mac-tahoe-timing-issues/5804)
**Author:** [@keith](https://psychtoolbox.discourse.group/u/keith)\ **Replies:** 18\ **Last updated:** [April 17, 2026, 2:19pm UTC](https://psychtoolbox.discourse.group/t/quick-fix-for-mac-tahoe-timing-issues/5804 "2026-04-17T14:19:44Z")
Hi all, I just wanted to report a trick that fixed the timing for me. So now I’ve upgraded to Mac OS 26.5 beta. I don’t know if this works on previous versions or not. I tested this using Octave 11.1 and PTB 3.0.22. My… --- ## [Invalid MEX-file error on MATLAB](https://psychtoolbox.discourse.group/t/invalid-mex-file-error-on-matlab/5797)
**Author:** [@Ghu](https://psychtoolbox.discourse.group/u/Ghu)\ **Replies:** 1\ **Last updated:** [April 3, 2026, 6:18pm UTC](https://psychtoolbox.discourse.group/t/invalid-mex-file-error-on-matlab/5797 "2026-04-03T18:18:26Z")
Hello, I am programming with MATLABR2023a for academic use and have encountered this error message several times: Invalid MEX-file ‘C:\\Psychtoolbox\\PsychBasic\\MatlabWindowsFilesR2007a\\Eyelink.mexw64’: The network path w… --- ## [KbQueueCheck Documentation](https://psychtoolbox.discourse.group/t/kbqueuecheck-documentation/5803)
**Author:** [@pscarfe](https://psychtoolbox.discourse.group/u/pscarfe)\ **Replies:** 7\ **Last updated:** [March 18, 2026, 6:12pm UTC](https://psychtoolbox.discourse.group/t/kbqueuecheck-documentation/5803 "2026-03-18T18:12:48Z")
I am sure this is just being dumb. I have been working all weekend on admin which has rotted my brain. The documentation for KbQueueCheck states “Obtains data about keypresses on the specified device since the most rec… --- ## [Code check: Unusual reaction times (like less than 100 ms) for an AX-CPT task coded using PTB version 3.0.19](https://psychtoolbox.discourse.group/t/code-check-unusual-reaction-times-like-less-than-100-ms-for-an-ax-cpt-task-coded-using-ptb-version-3-0-19/5798)
**Author:** [@tylerdurden9591](https://psychtoolbox.discourse.group/u/tylerdurden9591)\ **Replies:** 1\ **Last updated:** [March 13, 2026, 8:09am UTC](https://psychtoolbox.discourse.group/t/code-check-unusual-reaction-times-like-less-than-100-ms-for-an-ax-cpt-task-coded-using-ptb-version-3-0-19/5798 "2026-03-13T08:09:26Z")
I am coding an AX-CPT task using PTB in MATLAB and while doing pilot testing, I am getting unusual RTs (Less than 100ms) when the participant is trying to do the task fast. Below are the details of the environment I am u… --- ## [Windows 11 Compatibility - requesting a statement to show IT](https://psychtoolbox.discourse.group/t/windows-11-compatibility-requesting-a-statement-to-show-it/5794)
**Author:** [@Dagmar](https://psychtoolbox.discourse.group/u/Dagmar)\ **Replies:** 3\ **Last updated:** [March 4, 2026, 4:29am UTC](https://psychtoolbox.discourse.group/t/windows-11-compatibility-requesting-a-statement-to-show-it/5794 "2026-03-04T04:29:51Z")
Hey Mario! We have been trying to request Windows 10 LTSC Edition from our Central IT as a back up for our upcoming fleet of Ubuntu machines - this will enable legacy paradigm to run without tweaking - and sidesteps the… --- ## [Eyelink calibration freeze in fullscreen on Apple Silicon Macs](https://psychtoolbox.discourse.group/t/eyelink-calibration-freeze-in-fullscreen-on-apple-silicon-macs/5769)
**Author:** [@wenp97](https://psychtoolbox.discourse.group/u/wenp97)\ **Replies:** 3\ **Last updated:** [March 3, 2026, 8:24pm UTC](https://psychtoolbox.discourse.group/t/eyelink-calibration-freeze-in-fullscreen-on-apple-silicon-macs/5769 "2026-03-03T20:24:16Z")
Hi all, I’m having a problem getting Eyelink calibration to work in fullscreen mode on Apple Silicon setup with the new version of psychtoolbox. Setup: • Eye tracker: Eyelink 1000 Plus (v 5.15) • Computer: Apple M2 Ul… --- ## [VBL endline beamposition queries and audio timestamping issues 2](https://psychtoolbox.discourse.group/t/vbl-endline-beamposition-queries-and-audio-timestamping-issues-2/5791)
**Author:** [@MBBP](https://psychtoolbox.discourse.group/u/MBBP)\ **Replies:** 4\ **Last updated:** [March 3, 2026, 6:46pm UTC](https://psychtoolbox.discourse.group/t/vbl-endline-beamposition-queries-and-audio-timestamping-issues-2/5791 "2026-03-03T18:46:58Z")
Psychtoolbox Version: 3.0.22 MATLAB Version: 2025b OS Name: Microsoft Windows 11 Enterprise Version: 10.0.22631 Processor: Intel(R) Core(™) Ultra 7 165H, 3800 Mhz, 16 Core(s), 22 Logical Processor(s) MATLAB: 9.13.0.… --- ## [Psychtoolbox 3.0.22.2 "The long long slog" 🫩](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-2-the-long-long-slog/5796)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [March 2, 2026, 10:10pm UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-3-0-22-2-the-long-long-slog/5796 "2026-03-02T22:10:39Z")
Psychtoolbox 3.0.22.2 “The long long slog” was released on 2nd March 2026. :face\_with\_bags\_under\_eyes: You can download it as a zip file from the following link: https://github.com/Psychtoolbox-3/Psychtoolbox-3/release… --- ## [First stimulus in Psychtoolbox trial consistently ~30 ms shorter than expected when chaining flips with vbl](https://psychtoolbox.discourse.group/t/first-stimulus-in-psychtoolbox-trial-consistently-30-ms-shorter-than-expected-when-chaining-flips-with-vbl/5786)
**Author:** [@YA87](https://psychtoolbox.discourse.group/u/YA87)\ **Replies:** 4\ **Last updated:** [February 15, 2026, 8:59pm UTC](https://psychtoolbox.discourse.group/t/first-stimulus-in-psychtoolbox-trial-consistently-30-ms-shorter-than-expected-when-chaining-flips-with-vbl/5786 "2026-02-15T20:59:57Z")
Hi everyone, I’m experiencing a consistent timing issue in my Psychtoolbox experiment. The very first stimulus in each trial (e.g., the fixation cross or the feedback after response window) is always about ~30 ms shorte… --- ## [GStreamer x Windows 11 issue](https://psychtoolbox.discourse.group/t/gstreamer-x-windows-11-issue/5782)
**Author:** [@ChildLabsAU](https://psychtoolbox.discourse.group/u/ChildLabsAU)\ **Replies:** 3\ **Last updated:** [January 28, 2026, 8:03pm UTC](https://psychtoolbox.discourse.group/t/gstreamer-x-windows-11-issue/5782 "2026-01-28T20:03:55Z")
support key: 0199aa85-0b7c-7d82-9ec1-6b585dd136b3 OS: Windows 11 (Acer PC) Matlab: R2024b PTB: latest stable (3.0.22.1) GStreamer: latest stable (1.26.10), “complete” install Hi, We’ve just had to update our OS fro… --- ## [Serial trigger to BrainVision TriggerBox stops working after OS upgrade (Windows 11)I](https://psychtoolbox.discourse.group/t/serial-trigger-to-brainvision-triggerbox-stops-working-after-os-upgrade-windows-11-i/5784)
**Author:** [@sg1021](https://psychtoolbox.discourse.group/u/sg1021)\ **Replies:** 5\ **Last updated:** [January 27, 2026, 4:07pm UTC](https://psychtoolbox.discourse.group/t/serial-trigger-to-brainvision-triggerbox-stops-working-after-os-upgrade-windows-11-i/5784 "2026-01-27T16:07:15Z")
Dear Community, Current environment: Windows 11 Psychtoolbox-3 (3.0.22.1) MATLAB R2025b Previous environment: Windows 10 Psychtoolbox-3 (3.0.19.3) MATLAB R2023 We run an EEG experiment using Brai… --- ## [Timing / Performance issues on macOS 26 Tahoe](https://psychtoolbox.discourse.group/t/timing-performance-issues-on-macos-26-tahoe/5767)
**Author:** [@keith](https://psychtoolbox.discourse.group/u/keith)\ **Replies:** 31\ **Last updated:** [December 21, 2025, 6:09pm UTC](https://psychtoolbox.discourse.group/t/timing-performance-issues-on-macos-26-tahoe/5767 "2025-12-21T18:09:22Z")
Something about Mac OS 26.1 seems to destroy the timing. Every frame flip is missed in VBLSyncTest and DotDemo, for example. Not sure if this is Matlab specific, because my Octave version had been updated to 10.3 and P… --- ## [Psychtoolbox is on christmas vacation from now on. Also, don't upgrade to macOS Tahoe! 🎄](https://psychtoolbox.discourse.group/t/psychtoolbox-is-on-christmas-vacation-from-now-on-also-dont-upgrade-to-macos-tahoe/5781)
**Author:** [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Replies:** 0\ **Last updated:** [December 21, 2025, 6:07pm UTC](https://psychtoolbox.discourse.group/t/psychtoolbox-is-on-christmas-vacation-from-now-on-also-dont-upgrade-to-macos-tahoe/5781 "2025-12-21T18:07:44Z")
:santa: Ho ho ho! Christmas is around the corner and I started my Christmas and new year vacation. Therefore user support is from now on suspended until mid January 2026. Also, I strongly advise the macOS users, and e… --- ## [Cant install run Psychtoolbox in matlab](https://psychtoolbox.discourse.group/t/cant-install-run-psychtoolbox-in-matlab/5779)
**Author:** [@taryngreen](https://psychtoolbox.discourse.group/u/taryngreen)\ **Replies:** 4\ **Last updated:** [December 21, 2025, 1:04pm UTC](https://psychtoolbox.discourse.group/t/cant-install-run-psychtoolbox-in-matlab/5779 "2025-12-21T13:04:15Z")
There are missing files. No it is not g streamer. when you download the files from the site, you do not get all the folders. There is one missing, what is it. You may have to add that separately. --- ## [I am recieving a value of 10 for the screen number when I only have 2 screens](https://psychtoolbox.discourse.group/t/i-am-recieving-a-value-of-10-for-the-screen-number-when-i-only-have-2-screens/5776)
**Author:** [@malmberg](https://psychtoolbox.discourse.group/u/malmberg)\ **Replies:** 1\ **Last updated:** [December 12, 2025, 6:53pm UTC](https://psychtoolbox.discourse.group/t/i-am-recieving-a-value-of-10-for-the-screen-number-when-i-only-have-2-screens/5776 "2025-12-12T18:53:54Z")
=== delete this after reading === Please make sure you read this post before asking for help. No one can help you unless you provide a clear description of the software environment you are using and your programming pro… --- ## [Compatibility Issues Between PTB and MATLAB Versions](https://psychtoolbox.discourse.group/t/compatibility-issues-between-ptb-and-matlab-versions/5775)
**Author:** [@ziyuan](https://psychtoolbox.discourse.group/u/ziyuan)\ **Replies:** 1\ **Last updated:** [December 12, 2025, 4:00pm UTC](https://psychtoolbox.discourse.group/t/compatibility-issues-between-ptb-and-matlab-versions/5775 "2025-12-12T16:00:59Z")
Hello everyone in the community! I’m posting this request for help on behalf of a colleague—since he’s new to the community, his account is restricted from posting directly. Recently, they’ve been trying to install PTB… --- ## [Ac\_compute\_device\_uuid's output is based on invalid pci bus info](https://psychtoolbox.discourse.group/t/ac-compute-device-uuids-output-is-based-on-invalid-pci-bus-info/5772)
**Author:** [@widmann](https://psychtoolbox.discourse.group/u/widmann)\ **Replies:** 2\ **Last updated:** [December 11, 2025, 6:40pm UTC](https://psychtoolbox.discourse.group/t/ac-compute-device-uuids-output-is-based-on-invalid-pci-bus-info/5772 "2025-12-11T18:40:13Z")
We have a low priority, mainly cosmetic issue: Screen(‘GetWindowInfo’, window) prints a message ac\_compute\_device\_uuid’s output is based on invalid pci bus info to the Octave console (we do not perceive any other obvi… --- ## [Problems installing PTB on Linux](https://psychtoolbox.discourse.group/t/problems-installing-ptb-on-linux/5759)
**Author:** [@theprof07](https://psychtoolbox.discourse.group/u/theprof07)\ **Replies:** 19\ **Last updated:** [November 13, 2025, 1:35am UTC](https://psychtoolbox.discourse.group/t/problems-installing-ptb-on-linux/5759 "2025-11-13T01:35:15Z")
The NeuroDebian site is not working so I cannot install PsychToolbox. The line “After selecting a release the setup code will be shown here.” is not being replaced with the needed commands after selecting the OS release… [Next page](https://psychtoolbox.discourse.group/latest.md?page=1)