Defraggler is a disk defragmentation tool developed by Piriform, designed to optimize the performance of hard drives. It reorganizes fragmented data, allowing files to be stored in contiguous sections, which can improve access speed and overall system efficiency. The software offers a user-friendly interface, enabling users to analyze their drives and select specific files or folders for defragmentation. Unlike some built-in defragmentation tools, Defraggler allows for more granular control, making it a popular choice for users looking to enhance their computer's performance without complex procedures.