# Unable to install psychtoolbox on windows

**URL:** <https://psychtoolbox.discourse.group/t/unable-to-install-psychtoolbox-on-windows/5599>\
**Category:** Programming Help\
**Tags:** windows\
**Created:** [December 20, 2024, 11:28pm UTC](https://psychtoolbox.discourse.group/t/unable-to-install-psychtoolbox-on-windows/5599 "2024-12-20T23:28:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sternlas](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@sternlas](https://psychtoolbox.discourse.group/u/sternlas)\
**Post date:** [December 20, 2024, 11:28pm UTC](https://psychtoolbox.discourse.group/t/unable-to-install-psychtoolbox-on-windows/5599/1 "2024-12-20T23:28:47Z")

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Hi, I am trying to install Psychtoolbox on Windows 10. I have previously been successful with installing it on this machine. I have tried different recent versions of Matlab but get the same error message. The error is:  
ERROR: Most likely cause: The Microsoft Visual C++ 2019 runtime libraries  
ERROR: are missing on your system.

ERROR: Execute the installer file vcredist\_x64\_2015-2019.exe, which is located in your Psychtoolbox/PsychContributed/ folder.  
ERROR: You must execute that installer as an administrator user. Exit Matlab before the installation, then restart it.  
ERROR: After fixing the problem, restart this installation/update routine.

ERROR: You can also just do a: cd(PsychtoolboxRoot); SetupPsychtoolbox;

ERROR: This will avoid a full download of Psychtoolbox over the internet and just finish the setup.

However, i have run the vcredist exe in the psychtoolbox folder (elevated) multiple times with the same result. I have tried uninstall/reinstall with the same result.

I get this error when running SetupPsychtoolbox from the PsychContributed folder.

Suggestions?

Thanks.

Larry Stern  
UT Austin

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<div class="post-metadata">

**Author:** ![rbosworth](https://avatars.discourse-cdn.com/v4/letter/r/45deac/32.png) [@rbosworth](https://psychtoolbox.discourse.group/u/rbosworth)\
**Post date:** [December 23, 2024, 6:04pm UTC](https://psychtoolbox.discourse.group/t/unable-to-install-psychtoolbox-on-windows/5599/2 "2024-12-23T18:04:49Z")

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Same issue here. Windows 11. Matlab 2018b.

Removed the 2015-2022 redistributable 32 and 64 versions. installed the provided 2019 version didnt work, so added the 32 and still didnt work.

I receive the exact same error as the original poster.

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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:** [December 23, 2024, 6:09pm UTC](https://psychtoolbox.discourse.group/t/unable-to-install-psychtoolbox-on-windows/5599/3 "2024-12-23T18:09:51Z")

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Which PTB version, and how did you install it?

If it is PTB 3.0.20.0 and you got it directly from a Git clone/checkout or via the source code zip files, instead of the commonly used and generally recommended 3.0.20.0.zip file then you’d need to “manually” install the license manager libraries - a new requirement. You’d have to run  
`downloadlexactivator(0,1)` from the Psychtoolbox-3/managementtools/ subfolder at the moment. This step for unusual install paths will be automated later, but not yet in the 3.0.20.0 beta release.

Other than that new one for 3.0.20.0, there are no known failure modes.