Hi Friend, I got that too the first time I tried. Apparently we have to use the command for "writing" data on the card first so that there will be data to be "read" once you try the command for "reading". Also just a quick reminder/disclaimer from the website where I got F3: I did the tests on a newly-purchased MicroSD card...I only had one file in the card which is the 2GB video file I used in the testing as mentioned in Post #1, although when I re-ran the test without deleting the video file, it didn't seem to get overwritten. Anyway the author of the file said that the program will overwrite/delete files only if the card has a problem (marked with underscore above). Hope this helps. EDIT: did you happen to "rename" or "put a label" on the MicroSD? I labeled mine as "MICROSD" as mentioned in the command I used as an example.