Embodiments of the present invention provide a system, method, and program product for defragmenting files on a hard disk drive. A computer system identifies a plurality of movable blocks on a hard disk drive. The computer system categorizes each of the movable blocks into a category based on the write count of each movable block, wherein the movable blocks categorized into a first category have higher write counts than the movable blocks categorized into a second category. The computer system relocates the movable blocks of the first category to a first group of one or more adjacent tracks, and the computer system relocates the movable blocks of the second category to a second group of one or more adjacent tracks, wherein the first group of one or more adjacent tracks and the second group of one or more adjacent tracks share, at most, one common track.