Situations in Which DEFRAG Cannot Run (96519)

The information in this article applies to:
    Microsoft MS-DOS operating system 6.0
    Microsoft MS-DOS operating system 6.2
    Microsoft MS-DOS operating system 6.21
    Microsoft MS-DOS operating system 6.22

This article was previously published under Q96519


Microsoft DEFRAG operates on the MS-DOS logical drive level only. Third-party partitioning utilities that modify or translate disk geometry (such as Disk Manager and SpeedStor) operate beneath the MS-DOS file system and are therefore transparent to DEFRAG.

DEFRAG cannot share access to a drive with other tasks; therefore, you cannot run DEFRAG if Windows or DESQview is running.


DEFRAG does not work in the following situations:
   Situation        Reason
   ----------       ------
   Network Drive    Network software usually does not allow full
                    single-tasking access to the entire drive,
                    including the file tables. Often network drives
                    (such as Novell NetWare) use another file system.

   CHKDSK Errors    Errors in the drive organization can cause
                    unpredictable results from DEFRAG. DEFRAG
                    identifies most CHKDSK errors while reading
                    the drive organization, and then refuses
                    to run until you correct them.

   Windows          DEFRAG cannot operate properly in a
                    multitasking or task-switching situation;
                    therefore, it detects Windows in real, standard,
                    and 386 enhanced modes and does not run.

   Task Swapper     DEFRAG cannot operate properly in a
                    task-switching situation; therefore, it detects
                    the MS-DOS Shell task swapper and does not run.

   Interlnk Drives  Interlnk is not designed to support defragmentation
                    and other low-level utilities. Specifically, it does
                    not implement interrupts 25 and 26.

   Fastopen         The Fastopen program tracks which files are located
                    in which clusters on your disk. DEFRAG rearranges
                    data on a cluster level, which confuses Fastopen.

   JOIN             JOIN does not allow normal access to a drive.

   SUBST            SUBST drives do not have their own file tables or
                    directories to optimize.
The products included here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

Modification Type: Major Last Reviewed: 11/19/1999
Keywords: KB96519