Firstly great product hence the 5 stars but 1TB of disk space makes it power hungry and in certain scenarios a single usb lead is insufficient. If you're thinking of purchasing there is a proviso you should be aware of. See below my message to Seagate technical support team, hopefully they will rectify the inadequate usb cable, otherwise go and purchase a dual power lead cable from Amazon.
"The supplied short usb cable provides inadequate power to the 1TB Seagate Expansion Portable drive. Particularly if it's drawing power from PC the single usb cable is not up to the task. I was mistaken in thinking there was a problem with my portable hard disk and I returned product back to Amazon, who very kindly dispatched another and I duly received in the next couple of the days (excellent customer service, as always). I was reading on the Tech forum that certain portable hard disks require dual supply usb lead as some units require voltage in access of 500mva. I began to think that this might have been the problem with the Seagate.
On receiving the replacement product, I quickly put it through the test and much to my disappointment, I was experiencing the same erratic problem as before, i.e. it refuses to copy data onto the hard drive.
I had a dual usb supply lead from an existing external portable drive, which I borrowed. I swap the original Seagate usb lead with the dual lead and everything worked perfectly. The data from the PC transferred onto the portable at record speeds, 23 gb of data in less than 3 minutes. I suggest strongly that you replaced the generic single supply lead with a dual powered usb lead to avoid unnecessary complications with consumers. Less RMA's more happy customers!"
Regards
Jason