arduino creates strange files in SD card
I've had similar issues with large (> 1Gb) SD cards, I've had various different problems with different cards, some things that helped me debugging the problem:


make sure your wires are the same length and try to use short wires
make sure your power supply is sufficient, sd card readers can draw up to 150mA
format the card in either FAT16 or FAT32 and never use "quick erase", try to use official tools (like https://www.sdcard.org/downloads/formatter_4/index.html)
make sure if you're the correct BAUD rate (9600) to talk to your card
filename support is pretty old so keep them short and don't use spaces or special characters
make sure the SD card is not in "write lock" mode, there's a small switch on the side of some SD cards that can prohibit writing (but will allow reading)