MS-DOS DEFRAG Err Msg: "Insufficient Memory..." (95819)

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 6.22

This article was previously published under Q95819


This information applies to both Microsoft DoubleSpace and Microsoft DriveSpace. For MS-DOS 6.22, use DRVSPACE in place of DBLSPACE for commands and filenames.


If there are too many files and directories on your hard drive, MS-DOS Defragmenter (Defrag) can run out of memory. If Defrag runs out of memory before beginning optimization, the following error messages are displayed:

Insufficient memory - Error Reading the FAT


Insufficient Memory: Error Reading Directory


Defragmenter is limited by the number of files/directories and NOT the disk size. It is unlikely that this problem will occur unless you have more than 10,000 files/directories on your drive; however, it has occurred with as few as 8,000 files/directories.


You may be able to alleviate the problem by increasing the amount of free conventional memory and available upper memory blocks (UMBs). Refer to the "Microsoft MS-DOS User's Guide" for version 6.0 for additional information about freeing conventional memory.

If you get out-of-memory errors with MS-DOS 6.2 Defrag, increase conventional memory and/or XMS memory (up to 384K). MS-DOS 6.2 Defrag uses up to 384 kilobytes (K) of extended (XMS) memory, when available, to hold the FAT data for the drive.

If you have freed as much conventional memory as possible and you are using a 386 or 486 machine, try the following temporary workaround:

    Make sure EMM386.EXE is being loaded in the CONFIG.SYS file.
    Using an ASCII text editor such as MS-DOS Editor, add the I=A000-B7FF and NOEMS parameters to the device=C:\DOS\EMM386.EXE line in the CONFIG.SYS file.

    Note: The A000-B7FF range is commonly used by video cards. Unless you have a monochrome video card, do not run any graphics applications when you are using the I=A000-B7FF parameter.
    Save the CONFIG.SYS file and quit the text editor.
    Restart your computer.
    Run Defragmenter with the /G0 switch to prevent it from running in graphics mode. For example, you would type:

    defrag /g0

    NOTE: The switch is G and the number zero, not G and the letter O.
    Edit your CONFIG.SYS file and remove the parameters you added in step 2.
    Save the text file, exit the editor and restart your computer.
If, after following the above procedure, you continue to run out of memory when you attempt to defragment your drive, you probably have more files than Defragmenter can handle. To optimize your disk, you need to remove some files from your disk. If this problem occurs frequently, you may want to consider creating smaller partitions or multiple DoubleSpace drives on the same partition.

NOTE: If you are running Delete Sentry, you may want to run UNDELETE /PURGE to remove deleted files from the SENTRY directory.

Modification Type: Major Last Reviewed: 11/19/1999
Keywords: KB95819