The SD Memory Card Formatter formats SD Memory Card, SDHC Memory Card and SDXC Memory Card (respectively SD/SDHC/SDXC Cards) complying with the SD File System Specification created by the SD Association (SDA).
Could be the three wire power supply is not connected optimally. Sudden BAT line cut would corrupt the last file being recorded. All three wires need to be connected correctly.
I had this problem when I first setup my K2. I has connected it to a switched power source. So when I shut off my bike it would immediately turn off. The files that were recording at the time wouldn't be saved properly and wouldn't play. Once I connected it to an always on source, with the yellow wire to the switched source, it has worked perfectly since.