I bought the Lexar 64GB 800x card last year and had occasional problems downloading images. I purchased the Lexar USB3 card reader and after a trip in Finland the card Bear Became corrupted while reading the files. Problem: UDMA7 card in a slow reader. The Lexar Reader or older USB3 readers corrupt the card !!! Lexar do have a firware update to make Their old card reader compatible UDMA7 .... but this thing not known.