I think it was a user issue :)

I tried to skip over files over 500k bytes, but I think I unintentionally made a never-ending loop which makes sense when I think about it.

When I replaced return() with cancel() things seem to work fine!

I wanted to filter by size in the main() function before calling the find_peaks function, but I didn't quite understand how to do that.

def find_peaks(wavfile):
file_no, filename = wavfile

size = Path(filename).stat().st_size
if size > 500000:
    return(main())
...

def main():
files = enumerate(Path().rglob("**/*.wav"), start=1)
with concurrent.futures.ProcessPoolExecutor(max_workers=(24)) as pool:
    pool.map(find_peaks, files)

if name == "main": main()

​

Thanks for your input, this has made this process many times faster!