Description of the problem:
For some reason, when I run my experiment on Pavlovia, it opens onto a white screen and does not change to the black background I have on the program. Therefore, when I run it on PsychoPy it works, and has a black background and you can see the white text instructions. However, this is not visible when you run the experiment on Pavlovia. I left the window open for 10 minutes to see if it would change and it still has not.
Please could you show your background colour as set in Experiment Settings/Display and also how you change it? I use a 2 x 2 norm rectangle as the first component if I want a routine to have a custom coloured background.