Have you ever checked your USB debugger , maybe it wasn't turned on .the Android file transfer app won't detect the device. Any other alternative for managing Android device on Mac?
Make sure your phone is still connected to your computer , and check to see if your USB debugging has been turned on .the Android file transfer app won't detect the device.
That has been addressed in a post above.Make sure your phone is still connected to your computer , and check to see if your USB debugging has been turned on ,