Disk issues refer to problems that can occur with computer storage devices, such as hard drives or solid-state drives. These issues can manifest as slow performance, data corruption, or the inability to access files. Common causes include physical damage, software errors, or insufficient storage space. To address disk issues, users can run diagnostic tools to check the health of their drives. Regular maintenance, such as defragmentation for hard drives and ensuring adequate storage space, can help prevent problems. Backing up important data is also crucial to avoid loss in case of a disk failure.