Originally Posted by GAC
He told me that if the USB drive is unplugged from a computer, after transferring data, without first clicking on a icon that tells you it's safe to disconnect it, it can corrupt the drive. I've used external HDs before and never heard of such a thing. My son uses one all the time and never has heard of this. So I don't know if this tech guy knows what he's talking about, and was just stumped at a solution.
He is right. It doesn't happen often, but it can and does happen. Always use the option of "ejecting device XYZ" before unplugging it.