KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q105207: PRB: KRNL386: Unable to Enter Protected Mode

Article: Q105207
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) 3.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

Windows 3.1 fails to boot and returns to MS-DOS with a "KRNL386: Unable to enter
Protected Mode" error message. This usually occurs after switching to the debug
version of Windows.

CAUSE
=====

Windows 3.1 was started with old files left over from an upgraded installation
of Windows 3.0 with the Windows 3.0 Software Development Kit (SDK).

RESOLUTION
==========

Replace the old files with the correct versions. The files of importance are
KRNL386.*, KRNL286.*, GDI.*, and USER.*. The old files are from 1990 and the new
files are from 1992. Sort by date, and replace these old files with the correct
versions.

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

It's generally a good idea to start with a fresh installation of Windows in a
clean directory when this problem occurs. This ensures that other obsolete files
are cleared from the upgraded 3.0 installation.

Additional query words: 3.10 no32bit

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.