G drive USB 3.1, mackbook prow with macOS Sierra

My drive was working fine, I don’t leave it plugged in, just once in a while plug it in and do a backup. The last time I tried to use it, the power light came on it shows up in finder but but it won’t open. The drive just makes a fairly loud click approximately every couple of seconds.

Make sure the computer is plugged in to power, the device won’t allow a backup unless your system is attached to power anyways and when on battery it causes less power throughput for the drive and can cause clicking.

If you were plugged in to power and this was occurring then it could be a hardware issue with the drive. You can try another USB cable or computer just to be sure but if that is all it does now then it would need to be replaced.