I’m having a similar problem. I just installed PsychoPy 3.0.0b12 on my standalone laptop and found that while the Builder come up, when I try to load an experiment, nothing happens. If I run psychpyApp from python.exe, everything seems to be fine. I do get a warning about the ‘OSF Project ID’ is not known.
(perceptionlab) C:\Users\data.collection>python -m psychopy.app.psychopyApp
Hello from the pygame community. https://www.pygame.org/contribute.html
7.4628 WARNING Parameter ‘OSF Project ID’ is not known to this version of PsychoPy but has come from your experiment file (saved by a future version of PsychoPy?). This experiment may not run correctly in the current version.
gitpython and a git installation required for getProject()
Maybe the problem is because pythonw.exe has no place to output error messages?
Actually, this may be a conda install issue. I didn’t have the Coder view up before, but when I brought up the Coder view and went to open the psyexp file, I got a message about gitpython and a git installation are required for getProject(). gitpython was installed in my conda environment, but if I try and import it into python, I get a ModuleNotFoundError.