Disk cleanup utilities are software tools designed to free up space on a computer's hard drive by removing unnecessary files. These files can include temporary files, system cache, and old installation files that are no longer needed. By regularly using a disk cleanup utility, users can improve their computer's performance and ensure that it runs more efficiently. Most operating systems, such as Windows and macOS, come with built-in disk cleanup utilities. Users can access these tools through their system settings, allowing them to select which types of files to delete. This process helps maintain optimal storage levels and can prevent issues related to low disk space.