If youve defragmented your hard drive and are still seeing subpar performance, you may need to fix disk errors on your hard drive. Hard disk errors are typically caused by power outages, hardware failures, poor system maintenance, viruses, or human error. To fix disk errors, you can use the Chkdsk tool found in Windows operating systems. Chkdsk (Chkdsk.exe) is a command-line tool that creates and displays a status report for the disk by checking volumes for problems. The tool then lists and corrects errors on the disk, such as bad sectors, lost clusters, cross-linked files, and directory errors. Heres how to use Chkdsk. Download Harddisk Defragment Tool to automatically fix hard disk errors.