Microsoft KB Archive/135308

= Disk Administrator Corrupts Partitions =

Article ID: 135308

Article Last Modified on 10/31/2006

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APPLIES TO


 * Microsoft Windows NT Workstation 3.51
 * Microsoft Windows NT Server 3.51

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This article was previously published under Q135308





SYMPTOMS
When you install Windows NT 3.51 and start Disk Administrator for the first time, Windows NT will write a disk signature to the drives before opening the Disk Administrator window.

The first time Disk Administrator is opened, drives and partitions appear correctly, but if you close and reopen it, some of the partitions are lost and incorrect information is displayed on the others. Alternatively, Disk Administrator can hang during initialization or the error message, "The parameter is incorrect" appears.

This only happens if there are more than two logical drives in an extended partition when Disk Administrator attempts to write a fault tolerance signature.

This problem will not occur if a signature is already present.

Another symptom of this problem is that any partition formatted as Windows NT File System (NTFS) will show 0 bytes available and 0 bytes free after the signature was written by WINDISK, but before the first reboot after the signature was written.



CAUSE
Windows NT Disk Administrator writes a fault tolerance signature to each physical drive's master boot record, if one is not already present, when it is run for the first time. Faulty calculations result in the corruption of logical drives in an existing extended partition.

NOTE: It is possible for a system to remain functional after the partition table is corrupted. The nature of the corruption is such that partition table data is written to incorrect locations on the disk which may lie in the middle of user or file system data. Provided this information is not overwritten, the partition table entries may still identify the layout of the drives sufficiently well that Windows NT can continue to access the drives. However, this is an unstable situation and access to the partitions will be lost when the table entries are eventually overwritten.

If the table entries overwrite existing data, user data or file system integrity are compromised immediately.

If you suspect that your partition table is compromised, immediately back up critical data, then re-partition your disk and restore the backed up data to the system.



RESOLUTION
To correct this problem:

 Install the latest U.S. Service Pack for Windows NT version 3.51.

-or- If your system has already been corrupted, but Windows NT still boots, obtain the file CORRECT.EXE to correct the partition table whenever possible.

CORRECT.EXE does not guarantee recovery of user data, it just means that the partition table is put back in its original state if possible, or at least a consistent state if there is not enough information to put it back in its original state. In the mean time, critical user or file system data may still have been irretrievably lost.

This program is also being distributed with the hotfix and both the fixed kernel and CORRECT.EXE are being posted to our external FTP server as well. Again, this is an unusual step that we are taking due to the seriousness of the problem.

For more information read the README.TXT file posted with CORRECT.EXE.

All files discussed here are publicly available from ftp.microsoft.com under:

\bussys\winnt\winnt-unsup-ed\fixes\nt351\windisk



To Prevent Partition Table Corruption

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If Disk Administrator has not been run, you can prevent partition table corruption by any of these 3 procedures:


 * If there are not already more than two logical drives in an extended partition, simply use Disk Administrator normally. The signature will be written correctly and no corruption should ensue. If there are more than two logical drives, perform a full system backup of data on all drives prior to running Disk Administrator. Then be prepared to delete and recreate the partition structure prior to restoring the previously backed up data.
 * If an earlier version of Windows NT is available, boot that version and run its Disk Administrator so that a fault tolerance signature is written to the disk. The 3.5 version of WINDISK.EXE may be run directly on Windows NT version 3.51 in order to write the initial fault tolerance signature, but is not recommended for systems using third-party partitioning software to support large IDE drives.
 * If you have the tools and knowledge to edit the disk at the sector level, you may manually enter a disk signature so that Disk Administrator will not try to do so. The 4-byte signature is located at offset 0x1b8 from the start of the Master Boot Record (physical sector 0). The value written is not important provided that it is non-zero, but if there are multiple disks in the system, each should have a distinct signature value. If this field is already non-zero, it is not necessary to change it.

CAUTION: Use this option at your own risk. Incorrectly editing physical disk sectors can result in corruption of the entire physical volume, resulting in loss of data and may require a complete reinstallation of the operating system.



STATUS
Microsoft has confirmed this to be a problem in Windows NT version 3.51. This problem has been corrected in the latest U.S. Service Pack for Windows NT version 3.51. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

S E R V P A C K

Additional query words: prodnt fdisk mbr

Keywords: kbother KB135308

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