Q235376: Disabling Autochk Causes Incorrect Volume Set Size

Article: Q235376
Product(s): Microsoft Windows NT
Version(s): 4.0
Operating System(s): 
Keyword(s): kbenv kbtool diskmem kbDiskMemory
Last Modified: 06-AUG-2002

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The information in this article applies to:

- Microsoft Windows NT Server version 4.0 
- Microsoft Windows NT Workstation version 4.0 
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IMPORTANT: This article contains information about modifying the registry. Before you 
modify the registry, make sure to back it up and make sure that you understand how to restore 
the registry if a problem occurs. For information about how to back up, restore, and edit the 
registry, click the following article number to view the article in the Microsoft Knowledge Base:

  Q256986 Description of the Microsoft Windows Registry

SUMMARY
=======

Although you can disable the automatic disk checking tool (Autochk.exe) that
runs at Windows NT startup, Microsoft does not recommend that you do so.
Disabling Autochk during the extension of a volume set can result in damage to
the volume set, loss of data, or an inability to use the space added to the
set.


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

WARNING: If you use Registry Editor incorrectly, you may cause serious problems
that may require you to reinstall your operating system. Microsoft cannot
guarantee that you can solve problems that result from using Registry Editor
incorrectly. Use Registry Editor at your own risk.

When you extend a volume set, Disk Administrator updates the BootExecute value
under the following registry key, appending the command "autochk /x
<drive_letter>":

  HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager

This causes the NTFS indices to be rebuilt and the additional capacity to be
added to the volume set.

If this step is not performed, Disk Administrator may report the new disk to be a
part of the volume set, even though File Manager or the command prompt still
shows the previous capacity. Another possibility is corruption of the entire
volume set. Your only option may be to delete and re-create the volume set, and
then restore from backup.

If an incorrect capacity is reported, you may be able to resolve the situation by
adding a command to run Autochk to the BootExecute value in the registry key
listed above. You can try adding the following data value for the BootExecute
value:

  autocheck autochk *
  autochk /x <drive>:

Note that you must press ENTER after "autocheck autochk *".

Then, shut down and restart the computer. When the computer restarts, Chkdsk runs
and the volume set is verified. This process may take a long time, but you must
allow it to continue. If the process is successful, the volume set reports the
correct size.


Additional query words: autocheck autocheck.exe autochk.exe

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Keywords          : kbenv kbtool diskmem kbDiskMemory 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : :4.0
Issue type        : kbinfo

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