KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q87269: Windows Err Msg: Unable to Start Enhanced Mode…Back Fill

Article: Q87269
Product(s): Microsoft Windows 95.x Retail Product
Version(s): 3.0,3.0a,3.1,3.11
Operating System(s): 
Keyword(s): 
Last Modified: 06-FEB-2002

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

- Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 
-------------------------------------------------------------------------------

SYMPTOMS
========

The following error message is displayed when you try to start Windows in 386
enhanced mode:

  EMM386: Unable to start Enhanced Mode Windows due to base memory back fill

CAUSE
=====

This message appears if either of the following conditions is true:

- Your memory manager is configured to back fill base memory.

  -or-

- Conventional memory is improperly set in the CMOS settings; that is,
  conventional memory is set to 512 kilobytes (K) instead of 640K.

RESOLUTION
==========

To correct this problem, reconfigure your CMOS settings or disable base memory
back fill.

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

On systems with CGA or Hercules video cards, the A000-AFFF memory range is
available for base memory back fill or as upper memory blocks. If the memory is
used to back fill base memory, the MEM and CHKDSK commands generally report more
than 640K conventional memory available. 386 enhanced mode is not compatible
with base memory back fill.

When using EMM386.EXE, consider the following:

- Do not include the A000-AFFF memory range by removing the I=A000-AFFF
  statement on the EMM386 device line in the CONFIG.SYS file. EMM386.EXE does
  not use the A000 range by default.

  -or-

- Include only A0FF-AFFF and use it with the NOEMS or RAM switch to load
  devices high with MS-DOS version 5.0 or later. For example:

  DEVICE=C:\WINDOWS\EMM386.EXE NOEMS I=A0FF-AFFF

  -or-

- Run Windows 3.1 in standard mode by typing "win /s" (without the quotation
  marks) at the MS-DOS command prompt.

OTHER MEMORY MANAGERS
---------------------

386MAX:

If you use 386MAX by Qualitas to back fill base memory, the following error
message is displayed:

  386MAX VxD Error: NOLOW option required. 386MAX VxD not loaded. Windows
  initialization terminated. Press any key to return to DOS.

To eliminate this problem, edit the 386MAX.PRO file in the 386MAX directory and
add the line "NOLOW" (without the quotation marks). This includes the A000 range
as upper memory address space as opposed to back filling.

For more information on the NOLOW feature and 386MAX.PRO, consult your 386MAX
documentation or contact Qualitas.

QEMM386:

If you back fill with Quarterdeck's QEMM386, the following error message is
displayed:

  Either memory is insufficient to run KRNL386.EXE or the value of the
  Windowmemsize entry in the SYSTEM.INI is too large. You need to run the Setup
  program again.

To work around the problem, use QEMM to disable the base memory back fill by not
including the A000 range or by only including A0FF-AFFF.

NOTE: Increasing available memory, adjusting the Windowmemsize value in the
[386Enh] section of the SYSTEM.INI file, or running the Windows Setup program
will have no effect on the error message.

For more information about including memory ranges, please refer to your QEMM
documentation or contact Quarterdeck.

The products included here are manufactured by vendors independent of Microsoft;
we make no warranty, implied or otherwise, regarding these products' performance
or reliability.

Additional query words: 3.00 3.00a 3.10 3.11 err msg backfill Compuadd

======================================================================
Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311
Version           : :3.0,3.0a,3.1,3.11

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

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.