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Issues Running Experiment in Open Sesame

Hi there,

I am looking for some help with an issue running an experiment that was built on Open Sesame(3.2.5) on a newer version of Open Sesame (3.2.8).

We are using a Mac Mini running OS El Capitan and an EyeLink eye tracker. Open Sesame is the most up to date version (3.2.8). I am trying to run an open sesame experiment that was created in version 3.2.5. The experiment will run the instruction section, but after this the experiment crashes and ends itself before reaching the practice and testing stages and prints out this error:

Imageio: 'ffmpeg-osx-v3.2.4' was not found on your computer; downloading it now.

Error while fetching file: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:726)>.

The program also tells me, in a later message, that it:

Failed to read .xlsx file: /var/folders/cb/nj7_6t9x7lb6tx5d9l_tl_cm0000gn/T/tmpP2xOHx.opensesame_pool/practice_list.xlsx

I was wondering if anyone could help clear this up for me! Thanks!


  • Hi Cayley,

    The first message, about ffmpeg, reflects that OpenSesame fails to download the software that is necessary for running video files. That's probably harmless in your case.

    The second message, about not being able to read the .xlsx file, probably reflects that the openpyxl library is not installed, due to a packaging issue on Mac OS. You can see how to fix that in this discussion:



    There's much bigger issues in the world, I know. But I first have to take care of the world I know.

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