question regarding.flush() command

mschramm:

Where to begin???

  for (uint8_t i = 1; i < 100; i++) {
    filename[6] = '0' + i/10;
    filename[7] = '0' + i%10;
    if(i==99){
      g=1;
    }

When this loop ends, the 7th and 8th characters in filename will both be 9, i will be 99 and g will be 1....every time you try to create a new file! I presume that's not what you want. I would keep a record of the last file number used and increment this every time you want to create a new filename. Something like this:

 int i = 0; //put this before setup()
create new filename...
    i++;  //numbering starts at 01 and goes up to 99.
    if(i==100){
      g=1;
      i = 0; // max exceeded, so reset counter
             // warn max exceeded and file not created, here
    }
    else{  
      filename[6] = '0' + i/10;
      filename[7] = '0' + i%10;
     // create new file here
    }