Microsoft KB Archive/74589

= Hidden System Files and MS-DOS 5 and Later Upgrade =

Article ID: 74589

Article Last Modified on 11/16/2006

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APPLIES TO


 * Microsoft MS-DOS 5.0 Standard Edition
 * Microsoft MS-DOS 5.0a
 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition

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This article was previously published under Q74589



SUMMARY
The Microsoft MS-DOS Upgrade Setup copies the hidden system files IO.SYS and MSDOS.SYS to the front of the root directory in the boot drive. If the previous version of DOS had files called IO.SYS and MSDOS.SYS created by Microsoft, those files will be deleted.

If the previous version of DOS has hidden system files by other names or that were not created by Microsoft, they are moved to the first available space in the root directory of the bootable hard drive. These files can then be deleted after resetting the file attributes.

The following command will turn off the system file attribute, the hidden file attribute, and the read-only file attribute of a file named IBMBIO.COM.

attrib -s -h -r ibmbio.com

These files can also be deleted using MS-DOS Shell.

Additional query words: 6.22 5.00 5.00a 6.00 6.20

Keywords: KB74589

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