An external command starting with DOS 5 that restores a formatted disk to its previous contents, providing it was formatted under DOS 5 without the /S switch. The /S switch bypasses saving Unformat information during the format process (see DOS Format).

Unformatting is not guaranteed. However, you can find out if you can unformat the disk before doing it. For example, to test the disk in drive A, type:

             unformat a: /test

To unformat the disk in drive A, type:

               unformat a: /u

Also see DOS Mirror for additional ways Unformat is used in data recovery.

In Windows 95, the Unformat command was eliminated.