# OSX and Matlab 2019b issue **URL:** \ **Category:** Uncategorized\ **Created:** [September 27, 2019, 12:44pm UTC](https://psychtoolbox.discourse.group/t/osx-and-matlab-2019b-issue/869 "2019-09-27T12:44:57Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![peter.scarfe](https://avatars.discourse-cdn.com/v4/letter/p/e9a140/32.png) [@peter.scarfe](https://psychtoolbox.discourse.group/u/peter.scarfe)\ **Post date:** [September 27, 2019, 12:44pm UTC](https://psychtoolbox.discourse.group/t/osx-and-matlab-2019b-issue/869/1 "2019-09-27T12:44:57Z")
I realise this is going to be a very low priority issue, however I thought I might as well report it. To save others a headache. All PTB demos I have tried abort under OSX 10.14.6, Matlab 2019b.  Here is the output for one demo (it is the same error with any demo I have tried) > \>\> DriftDemo PTB-INFO: This is Psychtoolbox-3 for Apple OS X, under Matlab 64-Bit (Version 3.0.16 - Build date: Aug  5 2019). PTB-INFO: OS support status: OSX version 10.14 is not officially supported or tested at all for this release. PTB-INFO: Type 'PsychtoolboxVersion' for more detailed version information. PTB-INFO: Most parts of the Psychtoolbox distribution are licensed to you under terms of the MIT License, with PTB-INFO: some restrictions. See file 'License.txt' in the Psychtoolbox root folder for the exact licensing conditions. INTERNAL PSYCHTOOLBOX ERROR error:                PsychError\_InvalidWindowRecord general description:  An Invalid window record was referenced. module name:          Screen subfunction call:     WindowKind file name:            /Users/kleinerm/projects/OpenGLPsychtoolbox/Psychtoolbox-3/PsychSourceGL/Source/Common/Screen/WindowHelpers.c function name:        PsychCheckIfWindowRecordIsValid line number:          61 Error using Screen See error message printed above. Error in sca (line 22)     if Screen('WindowKind', win) == 1 Error in DriftDemo (line 138)     sca; The same demos work fine under OSX 10.14.6, Matlab 2019a on the same machine (MBP Late 2016). So it seems Matlab 2019b is what is triggering things.  I have not had the chance to try PTB + Matlab 2019b on Windows or Linux, as we have largely transitioned away from PTB and Matlab, so do not have immediate access to these setups. I could probably test under Windows next week sometime if that is of any help.  No need for the usual snarky "upgrade" to Linux replies etc, etc, etc. These are very well rehearsed by now.  ---
**Author:** ![ianzolina](https://avatars.discourse-cdn.com/v4/letter/i/da6949/32.png) [@ianzolina](https://psychtoolbox.discourse.group/u/ianzolina)\ **Post date:** [September 27, 2019, 9:25pm UTC](https://psychtoolbox.discourse.group/t/osx-and-matlab-2019b-issue/869/2 "2019-09-27T21:25:04Z")
I have used 2019b with Linux and Windows, and I didn't see these error messages BTW. ---
**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\ **Post date:** [September 28, 2019, 6:56pm UTC](https://psychtoolbox.discourse.group/t/osx-and-matlab-2019b-issue/869/3 "2019-09-28T18:56:51Z")
It's yet another bug in Apples trainwreck, this time related to GUI operations and multi-threading. One of two new impressively dumb bugs i found, apart from the even worse display timing bug, because not only all good things come in three. I think it was introduced a couple of trainwreck releases ago, but had more minor effects, e.g., that when onscreen windows get closed then often the screen gets stuck, not switching back to the GUI again, unless one does random mouse clicking. At some recent point, Apple redefined this design defect into a "feature" iow. they documented the new and backwards incompatible rules wrt. GUI and multi-threading, because why behave like a half-way responsible operating system vendor just because you make an operating system? While the bug is clearly in macOS and fully Apples fault, it needs specific multi-threading design patterns in the host application to trigger and express the bug in all its glory. That's why the same macOS bug shows different symptoms with different runtime environments. The problem got much worse with 10.14 Mojave, but so far it only really badly affected GNU/Octave, which basically abort's immediately if you try to open an onscreen window on Mojave, while working fine on older macOS releases. Matlab up to R2019a got away by dumb luck, where only closing the onscreen window got completely stuck - a problem we counteract by opening a figure window needlessly at each session, because for whatever reason that fixed the "stuck window" problem on Mojave, see [https://github.com/Psychtoolbox-3/Psychtoolbox-3/blob/master/Psychtoolbox/PsychJava/PsychJavaSwingCleanup.m#L27](https://github.com/Psychtoolbox-3/Psychtoolbox-3/blob/master/Psychtoolbox/PsychJava/PsychJavaSwingCleanup.m#L27) for our madness to counteract the iToys companies madness. With Ian's and Peter's results on R2019b it seems the luck of Matlab users has run out, and whatever Mathworks changed internally now triggers the same crash sequence on 10.14+ as previously only on Octave. Luckily Octave aborted with some bunch of useful error messages, whereas Matlab somehow just silently fails and aborts 'Openwindow' in the middle of C-Code execution, probably due to differences in exception handling, and the PTB script continues running with damaged internal data structures, leading to that totally bogus error message about invalid window records in Screen('Windowkind'). Anyway, i do have - quite horrifying and shaky - workarounds for the two new Mojave bugs, and Ian's testing on the GitHub issue already shows they seem to work with R2019b. However, these workarounds are part of some contract work, so it depends on the specifics of how that contract goes if and when these fixes get released. -mario On Fri, Sep 27, 2019 at 11:48 PM [iandol@...](mailto:iandol@...) [PSYCHTOOLBOX] \<[PSYCHTOOLBOX@yahoogroups.com](mailto:PSYCHTOOLBOX@yahoogroups.com)\> wrote: > \> > \> > \> > \> Hm, I have a github issue open on the same error message, which I thought was caused by the fact I'm using macOS Catalina public beta: > \> > \> > \> [https://github.com/kleinerm/Psychtoolbox-3/issues/156](https://github.com/kleinerm/Psychtoolbox-3/issues/156) > \> > \> But yes, I'm also using 2019b, and so it seems my error is not an OS problem but a MATLAB one. Not sure what could be causing this, but I can confirm the same error messages. > \> > \> Ian > \> > \>