Q140372: Direct Disk Access Disabled to Protect Long File Names

Article: Q140372
Product(s): Windows for Workgroups and Windows NT Networking Issues
Version(s): WINDOWS:95; winnt:3.51
Operating System(s): 
Keyword(s): win95
Last Modified: 08-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Workstation version 3.51 
- Microsoft Windows NT Server version 3.51 
- Microsoft Windows 95 
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SYMPTOMS
========

When you install Windows NT 3.51 by running Winnt from a Windows 95 MS-DOS
prompt, the following error may occur as Setup is copying files:

  Windows has disabled direct disk access to protect your long file names. To
  overwrite this protection see the LOCK /? command for more information.

  The system has been halted. Press CTRL+ALT+DEL to restart your computer.


CAUSE
=====

Direct disk writes using INT 26h or INT 13h fail under Windows 95. This is
necessary in a multi-tasking environment to prevent disk corruption from
multiple utilities running simultaneously or prevent loss of long file names by
applications that are not long file name aware.

The LOCK and UNLOCK commands can be used to work around this protection for DOS
utilities (for example, Winnt) if necessary.

Use the following syntax for running LOCK:

  lock <drive_letter>:

Use the following syntax for running UNLOCK.EXE:

  unlock <drive_letter>:

RESOLUTION
==========

To lock a drive to enable direct disk access for Windows NT Setup, do either of
the following:

- Boot with the Windows 95 Emergency Startup Disk and at the MS-DOS prompt
  type:

  lock <drive_letter_to_lock>:

  For example:

  lock c:

-or-

- From within Windows 95, select Shutdown from the Start button and choose to
  Restart the Computer in MS-DOS mode. At the DOS Prompt type:

  lock <drive_letter_to_lock>:

  For example:

  lock c:

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

The error message above is a Windows 95 message and only appears if you start
Windows NT Setup by typing Winnt. If you install from the Windows NT compact
disc using boot floppies, this error message does not occur because Windows 95
must be running at the time to cause this error.

Additional query words: prodnt

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Keywords          : win95 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNT351search kbWinNTW351search kbWinNTW351 kbWinNTSsearch kbWinNTS351 kbWinNTS351search kbWin95search kbZNotKeyword3
Version           : WINDOWS:95; winnt:3.51

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