I have a 500Gb USB drive with is perhaps 6 or 7 years old but I hardly use it -- I use it only as a secondary data store and have written to it only a few times. I have made a new partition on it and given it a full format but the same thing happened as has plagued my use of this drive: many of the files and folders are corrupted as soon as they hit the drive, so don't get copied. What does this mean? What can I do? TIA.