Hello, you can try using another USB cable. You can also try testing the hard drive using DLG on Windows and Disk Utility on Mac. Check the link below for the steps. If the test fails, you should backup all of your files are replace the hard drive.
I’ve change the cable (10 euro), very difficult to find it… there is the same problem! The cable wasn’t the problem!!
DLG on Windows and Disk Utility on Mac run for too much time! For example, Disk Utility on Mac need moore than 48 hours for a low level format and probably past some hous that time will be increase (grrr…). Same with DLG (run for log time with no results).