Microsoft KB Archive/101565

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Article ID: 101565

Article Last Modified on 11/22/1999


  • Microsoft MS-DOS 6.0 Standard Edition

This article was previously published under Q101565


When you compress a drive using DoubleSpace, you may receive the following error message if the MS-DOS Fastopen program is running:

MS-DOS Fastopen Program has been detected!

Remove from your CONFIG.SYS or AUTOEXEC.BAT
file the command that installs FASTOPEN.
Then restart your computer and run DEFRAG again.

This causes the defragmentation process to abort. If DoubleSpace was running the Defragmenter (Defrag) to obtain enough contiguous space to continue compression, DoubleSpace attempts to run Defrag again and the above error is displayed again. You must restart your computer to prevent this error from recurring.


Before DoubleSpace begins compressing a drive, it checks the contents of the MS-DOS configuration files against the contents of the DBLSPACE.INF file. Because Fastopen is listed in the [Dangerous] section of DBLSPACE.INF, a REM command is placed in front of any line in the AUTOEXEC.BAT or CONFIG.SYS file that calls that utility.

During a first-time installation of DoubleSpace, the computer is then restarted, and Fastopen is removed from memory. However, if a drive is being compressed from the full-screen DoubleSpace maintenance program, the computer may not be restarted. In this case, if DoubleSpace runs Defrag, you continue to receive the above error message until you restart your computer.


To work around this problem, restart the computer using CTRL+ALT+DEL while the above error message is displayed on the screen. The edited configuration files are read and Fastopen is removed from memory. DoubleSpace can then continue with the compression process.


Fastopen is a disk-caching utility that originally shipped with MS-DOS 3.3 and ships today with MS-DOS 6. It can be run directly from the MS-DOS command prompt or loaded in either the CONFIG.SYS or AUTOEXEC.BAT file.

Additional query words: 6.00 doublespace manager dblspace

Keywords: KB101565