SCANDISK or ScanDisk is a utility in MS-DOS an Microsoft Windows systems which checks and repairs file systems and bad clusters on the hard drive. It was introduced in MS-DOS version 6.2. Previous versions of MS-DOS supplied only the simpler, purely text-based program CHKDSK. In Windows 95 onwards, SCANDISK also had a graphical user interface, although the DOS program retained the TUI. The disk scanning utility under Windows NT, Windows 2000 and Windows XP is also called CHKDSK (even though it is different from the MS-DOS CHKDSK) and has the ability to check NTFS disk drives. From Windows 2000 and on, it is integrated in Disk Properties as "error-checking".