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# IO.SYS & MSDOS.SYS File Sizes Don't Change After Uninstalling

Article ID: 100853

Article Last Modified on 11/22/1999

APPLIES TO

- Microsoft MS-DOS 6.0 Standard Edition

This article was previously published under Q100853

## SYMPTOMS

If you remove MS-DOS 6 Upgrade using the Uninstall disk you created during installation, IO.SYS and MSDOS.SYS still have the MS-DOS 6 file sizes (the original date and time are correct).

## CAUSE

This situation occurs because Uninstall overwrites the MS-DOS 6 IO.SYS and MSDOS.SYS files with the previous versions of IO.SYS and MSDOS.SYS but does not delete the MS-DOS 6 files first (nor does it truncate the files after overwriting them).

## MORE INFORMATION

Although this problem occurs with other versions of MS-DOS, the following table only shows the files sizes before and after installation and uninstall with MS-DOS 5.0 and MS-DOS 6.0.

                                                    MS-DOS 5 after
       File           MS-DOS 5        MS-DOS 6     Unstalling MS-DOS 6
       ---------------------------------------------------------------

       IO.SYS           33430          40470              40470
       MSDOS.SYS        37394          38138              38138

Additional query words: 6.00

Keywords: KB100853