DOCUMENT:Q119429  20-NOV-1999  [msdos]
TITLE   :ScanDisk Marks Valid Clusters Bad with Incorrect CMOS Settings
PRODUCT :Microsoft Disk Operating System
PROD/VER:MS-DOS:6.2,6.21,6.22
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft MS-DOS operating system versions 6.2, 6.21, 6.22 
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SYMPTOMS
========

When you perform a surface scan with ScanDisk, some valid, usable clusters are
designated as bad (unusable).

CAUSE
=====

This problem occurs if your CMOS settings are set incorrectly for your hard disk
drive. For example, if you have a 150-megabyte (MB) hard disk and the CMOS is
set for a 20-MB hard disk, ScanDisk scans the first 20 MB correctly, but the
remaining 130 MB are mark as bad.

RESOLUTION
==========

To correct your cluster entries:

1. Back up your files.

2. Correct your CMOS settings. (For more information, contact your hardware
   vendor.)

3. Run FORMAT /C /S to reformat the drive. (The /C parameter tells FORMAT to
   reexamine each cluster, and the /S parameter makes the drive bootable.)

   NOTE: Use the /S parameter only if the hard disk is your C drive.

4. Reinstall MS-DOS and Microsoft Backup.

5. Restore your data.


MORE INFORMATION
================

Running ScanDisk after you correct the CMOS settings does not correct the
problem. To avoid corrupting protection schemes that mark clusters bad, ScanDisk
does not change usable clusters marked as bad back to good.

Additional query words: 6.20 6.21 6.22 unused

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Keywords          :  
Technology        : kbMSDOSSearch kbMSDOS621 kbMSDOS622 kbMSDOS620
Version           : MS-DOS:6.2,6.21,6.22

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