performance – Why is my external hard drive uploading so slowly on USB 3.0?

I have approximately 1.5 TB of data which I need to back-up on an external hard drive. I am using a brand new 2 TB Seagate OneTouch HDD portable storage device with a USB 3.0 cable.

Currently, the expected transfer time is over 45 hours and climbing.

Maybe my math is wrong but 1.5 TB at 600 MBps using a USB 3.0 cable should only take about 45 minutes, right? Even if I was just using a USB 2.0 cable with 60 MBps, it still shouldn’t take much more than 7 hours.

What’s the issue here and is there some solution?