# Error on screen function using psychtoolbox 3 on matlab

**URL:** <https://psychtoolbox.discourse.group/t/error-on-screen-function-using-psychtoolbox-3-on-matlab/5155>\
**Category:** Programming Help\
**Tags:** windows\
**Created:** [November 1, 2023, 4:59pm UTC](https://psychtoolbox.discourse.group/t/error-on-screen-function-using-psychtoolbox-3-on-matlab/5155 "2023-11-01T16:59:01Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![s.martinez](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@s.martinez](https://psychtoolbox.discourse.group/u/s.martinez)\
**Post date:** [November 1, 2023, 4:59pm UTC](https://psychtoolbox.discourse.group/t/error-on-screen-function-using-psychtoolbox-3-on-matlab/5155/1 "2023-11-01T16:59:01Z")

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Hi everybody  
I am using acer travel mate p corei5 windows 11 PC and I have this issue on Matlab when running Psychtoolbox 3:

Unrecognized function or variable ‘Screen’.

Error in TloadDback\_Training\_Pretest (line 66)  
Screen(‘Preference’, ‘Verbosity’, 2); % Output for critical errors and warnings

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**Author:** ![dcnieho](https://avatars.discourse-cdn.com/v4/letter/d/779978/32.png) [@dcnieho](https://psychtoolbox.discourse.group/u/dcnieho)\
**Post date:** [November 1, 2023, 6:31pm UTC](https://psychtoolbox.discourse.group/t/error-on-screen-function-using-psychtoolbox-3-on-matlab/5155/2 "2023-11-01T18:31:54Z")

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You have not installed psychtoolbox correctly. Please follow the installation instructions on the website