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Opensesame Crashes system v3.2.5 OSX


Having an issue with Opensesame v3.2.5 (py2.7) on OSX 10.14. if I close the app and then relaunch it freezes the whole system before the GUI appears. The mouse is movable but the whole system crashes and I need to hard restart. This issue remains after restart and I have to uninstall the whole app and reinstall. the process begins again. Could it be a corrupt 'resume' state maybe? is there any way to start in safe mode or similar?

Best wishes,



  • Hi Kris,

    That sounds like a serious issue. These system-specific bugs are difficult to replicate and fix though, so for now your best bet is probably to try a different version and see if this does work. For example, @Daniel has recently packaged an experimental version based on Python 3, which you could give a try:


  • I'm having the same issue with OSX 10.14 and OpenSesame v3.2.5, and even when using @Daniel repackaged version for Python 3. The GUI appears but is slow, and then freezes with the spinning ball. After that the only way to exit OpenSesame is to use force quit.

  • Hi guys. I think this has to do with the Macos Mojave update. I haven't updated to Mojave yet and I plan on waiting a few patch updates (the first few releases of a new Macos version are always quite messy in my experience), so I have no way to reproduce these issues yet. Once I have updated I will dive into this.

    I do notice a difference in your reports though. For @kmccarty it is a system wide freeze while for @aaronjoh it is only the app that is frozen. Right?

    Do other qt5 apps (such as spyder ide for instance) show the same behavior for you? If so, then the problem may be related to compatibility between qt5 and Mojave, and may not necessarily be OpenSesame specific.
  • @Daniel : In my case it seems to be just OpenSesame specific, with other qt5 / Mojave apps working fine. Only OpenSesame freezes, not the system. I tried it as well on my desktop (running 10.12.6), OpenSesame works fine until I try to run the experiment (in either window or full screen), but then freezes at that point.

  • Just my two cents, but it could be completely unrelated. I always had issues with OpenSesame on Mac; i.e. app crashes and "funny" looking menus. I could never trace the source of these issues, but they all disappeared now that I installed OpenSesame in my Conda environment (which could suggest interference with the system environment).


  • I have updated to Mojave myself now, and OpenSesame indeed shows some quirks, although not as serious as the ones you describe. The issues appear to be mostly related to the hardware acceleration of the interface, and OS backends in my perception. I don't quickly know how I could fix this, as this is all quite low-level stuff, which I'm not very experienced with. My hope is that the dependency libraries that handle this will be updated soon and fix these problems.

  • These problems are likely caused by Mojave deprecating OpenGL in favor of Metal. (all the way at the bottom)
    Many parts of OpenSesame heavily rely on OpenGL, so it no longer being supported will definitely be a problem in the long run.

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