# Matlab freezes during older MacOS ptb install

**URL:** <https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336>\
**Category:** Bugs & Features\
**Tags:** macos\
**Created:** [April 5, 2022, 8:09pm UTC](https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336 "2022-04-05T20:09:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![sfo](https://avatars.discourse-cdn.com/v4/letter/s/4da419/32.png) [@sfo](https://psychtoolbox.discourse.group/u/sfo)\
**Post date:** [April 5, 2022, 8:09pm UTC](https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336/1 "2022-04-05T20:09:00Z")

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MacOS 10.12.6 Sierra, Matlab 2019a

I’ve done many many installs, and this is the first time I’ve encountered this. The install process proceeds as normal, then Matlab completely hangs on the final “Press ENTER if you understand” prompt. This occurs both with the DownloadPsychtoolbox installer as well as the full package SetupPsychtoolbox. After force quitting, it shows up in “ver” but running demos like DriftDemo2 or GarboriumDemo just hang.

Strangely, it worked ok in the past with the same computer and various Matlab versions, the only difference is the license has changed. Do I need to add some toolbox?

I can try a different Matlab version but 2019a is the newest you can install in Sierra. I can potentially upgrade the OS but I understand timing gets progressively worse, so where is the ideal, if not perfect, place I should stop? Mojave?

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**Author:** ![sfo](https://avatars.discourse-cdn.com/v4/letter/s/4da419/32.png) [@sfo](https://psychtoolbox.discourse.group/u/sfo)\
**Post date:** [April 5, 2022, 8:33pm UTC](https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336/2 "2022-04-05T20:33:14Z")

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Ah, I didn’t see there’s a background MATLAB crash dump. Pretty generic: “illegal instruction.”

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<div class="post-metadata">

**Author:** ![sfo](https://avatars.discourse-cdn.com/v4/letter/s/4da419/32.png) [@sfo](https://psychtoolbox.discourse.group/u/sfo)\
**Post date:** [April 5, 2022, 8:53pm UTC](https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336/3 "2022-04-05T20:53:49Z")

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Solved, I think. I had to revert to 3.0.16 and it was flawless. I don’t think this combo Sierra/2019a/3.0.17 is even supported/tested anymore, but just in case anyone else has the same problem, here it is.

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**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\
**Post date:** [April 6, 2022, 3:48pm UTC](https://psychtoolbox.discourse.group/t/matlab-freezes-during-older-macos-ptb-install/4336/4 "2022-04-06T15:48:17Z")

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Only 10.15.7 Catalina is tested and officially supported atm., but i think that macOS compatibility bug, caused by backwards compatibility bugs in Matlab, affecting everything older than 10.15, was fixed in PTB 3.0.18.1 and later, so upgrading to the latest PTB is the proper solution. The **untested** assumption is that current PTB should work ok on macOS 10.11 - 10.15.7 and on macOS 11/12 for Intel based Macs.

-mario