Finding missing files on a compact USB memory stick
You may not realize it but a USB flash drive is almost a computer of itself. These devices ranging in size from 1 to 32 GB have built into them static ram and read only flash memory. Once power is applied to the device it boots up just like a PC hard drive. And unfortunately, just like a PC, when the boot sectors become corrupted access to all stored files is denied. Most better grade USB drive recovery software recognizes this problem and works to circumvent it by directly accessing the stored files on that drive.
This is the same data recovery process needed to recover files from corrupted flash drive media used by digital media recovery tools to rescue damaged or deleted iPod files. Should the digital media recovery tool fail to access the stored files you must attempt what is known as “after the fact” recovery. This requires you to reformat the USB flash drive so as to restore its function and then scan the drive for deleted files. Because reformatted files are considered deleted, one can usually recover a high percentage of lost data in this way.