psychoJs in local debug mode - stuck at initialising the experiment

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): 2021.1.2
Standard Standalone? (y/n) y

Hi all. I routinely check the ‘run in local debug mode’ feature when I install newer versions of psychopy. I’ve never had much luck getting it to work. I’m on 2021.1.2 and I have an experiment that works fine in the builder (py) and on Pavlovia. I wanted to try the local debug mode to test modifications of the project.

When I try starting it, I just get a white “initialising the experiment” screen with no extra info on the console window. I’m loading conditions from an excell sheet and I’m importing image files.

Is the local debug expected to work out of the box? Or does it require extra configuration as to where files are placed or how paths specified? i.e. I remember a while back that one had manually modify the js script to specify absolute paths of resources ("unknown resource" file error when testing locally - #8 by arnon_weinberg) But in that instances that was a solution for missing resource errors. But in this case the problem doesn’t seem to be about resources that can’t be found…

Just wondering how this feature is supposed to work as it would make future workflows so much easier!

Thank you,

Another possibility is PsychoPy v2021.1 local debug mode not working though hard to guess what the problem is without an error message in the console.

I’m just stuck at initializing the experiment when I try to run from Builder. I don’t know if that’s the same problem or not, but any suggestions are welcome.
Experiment URL is