# Psychopy Encountered an unhandled error message

**URL:** <https://discourse.psychopy.org/t/psychopy-encountered-an-unhandled-error-message/25404>\
**Category:** Other\
**Created:** [October 14, 2021, 1:02am UTC](https://discourse.psychopy.org/t/psychopy-encountered-an-unhandled-error-message/25404 "2021-10-14T01:02:45Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Nadia\_Corral-Frias](https://avatars.discourse-cdn.com/v4/letter/n/3ab097/32.png) [@Nadia\_Corral-Frias](https://discourse.psychopy.org/u/Nadia_Corral-Frias)\
**Post date:** [October 14, 2021, 1:02am UTC](https://discourse.psychopy.org/t/psychopy-encountered-an-unhandled-error-message/25404/1 "2021-10-14T01:02:45Z")

</div>

I just installed the new version of psychopy and receive this error message:

wx.\_core.wxAssertionError: C++ assertion “(argtype & (wxFormatStringSpecifier::value)) == argtype” failed at C:\PROJECTS\bb2\dist-win64-py36\build\ext\wxWidgets\include\wx/strvararg.h(484) in wxArgNormalizer::wxArgNormalizer(): format specifier doesn’t match argument type

The above exception was the direct cause of the following exception:

Traceback (most recent call last):  
File “_ctypes/callbacks.c", line 234, in ‘calling callback function’  
File "C:\Program Files\PsychoPy\lib\site-packages\pyglet\window\win32\_init_.py”, line 661, in f  
event\_handler = event\_handlers.get(msg, None)  
SystemError: \<built-in method get of dict object at 0x0000029421FA4FC0\> returned a result with an error set