After 15 months of owning a SanDisk Clip Sport, I finally learned that not all micro USB cables will allow the player to transfer data with a PC (or Mac). The micro USB cable that comes with a Clip Sport is thicker than most other micro USB cables I have accumulated. So far only my SanDisk cable and a cable from my old Garmin GPS allow full data communication with my Clip Sport.
My many other non-data micro USB cables will allow charging of my Clip Sport (from a PC or A/C wall adapter). These cables are about 1/2 thickness of the SanDisk cable. Maybe a few of the data communication problems reported by Sansa users over the years were due to the selection of a non-data USB charging cable (and not the location of the USB port on their computer)?