It's not actually a clicking sound and not loud enough unless you put the HDD right next to your ear. It sounds just like when you play a CD or a DVD in your DVD drive as it looking for something but very quite. That sound appears for some time each time I plug it into the USB port and turns into smooth rotating sound after the computer detects nothing from it and right after the message appears as " You need to format the disk in drive G: before you can use it, Do you want to reformat it?". My HDD continously rotating smoothly just like my other HDD as long as it is plug into the USB.