ScanDisk Reports Undo Floppy Is Damaged (108603)

The information in this article applies to:
    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 Q108603


Running SCANDISK /UNDO results in the following error message:

The Undo information on the disk in drive A is damaged and cannot be retrieved.

To undo changes that ScanDisk made previously, insert an Undo disk in drive A, and then choose Try Again. If the Undo disk you want does not fit in drive A, insert the disk in the appropriate drive, and then restart ScanDisk by specifying the /UNDO switch and the appropriate drive letter (for example, SCANDISK /UNDO A:).

If you do not want to undo ScanDisk's changes, choose Exit.


This error occurs when the SCANUNDO.DAT file on the Undo disk has a read- only attribute, which ScanDisk attempts to clear before opening the file. Because the disk is write-protected, attempting to change the attribute fails and results in the above error.


Since ScanDisk needs to change the read-only attribute on the Undo disk, first verify that the disk is not write protected. If it is write- protected, remove the write-protect tab or slide the write-protect tab to the closed position, then try running SCANDISK /UNDO again. If the disk is not write-protected, the disk may be damaged. Run SCANDISK on the Undo disk to try to correct any problems on the floppy disk.

Modification Type: Major Last Reviewed: 10/27/2000
Keywords: KB108603