[[File: Drvspace.png|200px|thumb|right|DriveSpace replaced DoubleSpace in MS-DOS 6.22]]
MS-DOS 6.x was the last version of MS-DOS to be released on it's own. After MS-DOS 6.x, future versions of MS-DOS were released as part of Microsoft Windows. DOS 6.0 introduced a lot of new features such as help through QBASIC, antivirus and disk compression through DoubleSpace. However some users found some serious bugs. These bugs were fixed and scandisk was added in MS-DOS 6.20. Unfortunately Microsoft had infringed on Stacker's copyright by including DoubleSpace, so MS-DOS 6.21 was released that removed DoubleSpace. MS-DOS 6.22 however added DriveSpace.