I had that. Eventually the reader stopped working altogether. I just tossed it; never verified that it wasn't a driver problem (which was probably dumb on my part, but I had an external that worked fine.)
Scientific progress goes "Boink?"
Windows Gaming Box: AsRock Z77E-ITX / i5-3570k @ 4GHz / 8GB RAM / GTX 660Ti / Samsung EVO 250GB / Seagate Momentus 750GB / Silverstone SG05.
NAS: Foxconn D-70S-P (Celeron 1037U) / 4GB DDR3 / 4x Toshiba DT01ACA200, 1x DT01ACA300, 1x DT01ABA200, / Fractal Node 804.