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Builder crashing with hostapi/wdmks/pa_win_wdmks AssertionFailure

Hello there,

I have used psychopy before and now wanted to get into online studies.
However, I stumble at the first hurdle, with both v3.0.4 and -.5,.

After installation (win 10 pro, 64 bit), the coder view comes up, and changing to the Builder view
lead to a windows error message “Python has stopped working”, after which PsychoPy closes/crashes.

I tried whether running as admin changes this, and it does not.
Any ideas why this is happening and how I could get the Builder view to work?

Kind regards,

Some background info:
OS (e.g. Win10 Pro, 64bit):
PsychoPy version (3.0.4 (32 bit) and 3.0.5. (64bit)):
Standard Standalone? (y/n) y
What are you trying to achieve?: Open the Builder view to prepare an online study

(I do have a copy of Python 2.7 on my computer, which I use for small programming tasks,
like complex randomization procedures, just in case this might be an issue).

Most likely an error message is being swallowed before we get to see it. Could you open a command prompt and type something like this (you might need to point to the correct python.exe)

"C:\Program Files\PsychoPy2\python.exe" -m

Wow, thanks for the quick reply. This is the error message that appears in the command prompt:

A s s e r t i o n f a i l e d !

P r o g r a m : C : \ P r o g r a m F i l e s ( x 8 6 ) \ P s y c h o P y 3 \ p y t h o n . e x e
F i l e : s r c / h o s t a p i / w d m k s / p a _ w i n _ w d m k s . c , L i n e 1 0 8 1

E x p r e s s i o n : F A L S E

And that’s the entire message?!
Well, it looks like a problem with audio card. According to the link below it might be a broken audio driver, but if updating that doesn’t work then as a workaround I guess you could switch to using the pygame backend. To do that you’d need to manually edit your user prefs file which is in one of the windows appdata or roaming locations. You might be able to find it using

python -c "from psychopy import prefs; print(prefs.paths['userPrefsDir'])"

further info about portaudio assertion error (a slightly different one):

Thanks that helped. Turned out I have a good, but old sound card (Asus Xonar DX) on my computer, which works better with this unofficial driver on Win 10: