This article was previously published under Q100853
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If you remove MS-DOS 6 Upgrade using the Uninstall disk you created duringinstallation, IO.SYS and MSDOS.SYS still have the MS-DOS 6 file sizes (theoriginal date and time are correct).
This situation occurs because Uninstall overwrites the MS-DOS 6 IO.SYSand MSDOS.SYS files with the previous versions of IO.SYS and MSDOS.SYSbut does not delete the MS-DOS 6 files first (nor does it truncate thefiles after overwriting them).
Although this problem occurs with other versions of MS-DOS, thefollowing table only shows the files sizes before and afterinstallation and uninstall with MS-DOS 5.0 and MS-DOS 6.0.