id summary reporter owner description type status priority milestone component version resolution keywords cc port 62661 "py39-pyusb: ""No backend available"" error at runtime" programmingkidx reneeotten "I installed pyusb like this: sudo port install py-pyusb. py39-pyusb was installed. I then opened python 3.9 from here: /opt/local/bin/python3.9. When I imported the usb.core module there were no problems. But when I tried to run this program I saw the error about no backend available: import usb.core dev = usb.core.find(idVendor=0x0d8c,idProduct=0x0008) Here is the full error: Traceback (most recent call last): File """", line 1, in File ""/opt/local/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/usb/core.py"", line 1297, in find raise NoBackendError('No backend available') usb.core.NoBackendError: No backend available I tried to fix the problem by installing libusb like this: sudo port install libusb. This did not fix the problem. My info: Mac OS 11.1 M1 Mac Python 3.9" defect closed Normal ports 2.6.4 fixed py-pyusb