The replacement worked perfectly - for several weeks. Again, never moved, never dropped. One day, the PC stopped recognizing the external drive. Same problem (exactly) as experienced the first time. Called Maxtor support again; they again concluded drive was defective and sent a replacement. When questioned, Maxtor told me my problem was "quite unusual"; I have since discovered many, many complaints, just like mine, on the Internet.
AVOID MAXTOR ONE-TOUCH EXTERNAL DRIVES!