TestDisk is a free project for the verification and recovery of data from disk partitions that present serious mistakes and do not let access to the content.

Some failed programs or virus attacks can affect the units negatively impeding to function correctly. Luckily, TestDisk gives a hand and it will be in charge of returning all the files in the FAT12; FAT16; FAT32 and NTFS systems.

For that, it verifies the structure of the disk ad tries to repair the tables affected through complex operations but finally you will get what you are looking for.