DOCUMENT:Q168925 09-AUG-2001 [winnt] TITLE :Err Msg: The WIN16 Subsystem Was Unable to Enter Protected Mode PRODUCT :Microsoft Windows NT PROD/VER:4.0 OPER/SYS: KEYWORDS:kbenv kberrmsg ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server version 4.0 - Microsoft Windows NT Workstation version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When you attempt to run a 16-bit Windows-based program at a command prompt using the START command, you may receive the following error message: The WIN16 subsystem was unable to enter Protected Mode, DOSX.EXE must be present in you AUTOEXEC.NT and present in your path. However, Dosx.exe is present in the Autoexec.nt file and the file is in the path. CAUSE ===== This error message occurs when all of the following conditions exist: - The /separate switch is used with the START command. - There is a .pif file for the program in the path. - The .pif file references custom Autoexec and Config files that do not load Dosx.exe or Himem.sys. RESOLUTION ========== Rename the program's .pif file. Change the .pif file name from .pif, where is the executable file name of the program, to .xxx. Make sure to search for and rename all instances of the .pif file. MORE INFORMATION ================ The START command is a command-line tool that starts a separate window to run a specified program or command. It is frequently used in batch files. The /separate switch starts 16-bit Windows-based programs in separate memory space. When you use the START /SEPARATE .EXE command, the path is searched for any instances of a .pif file. If no .pif file is found, Windows NT loads the _default.pif file and then runs .exe. This behavior does not occur if the /separate switch is not used, nor does it occur in Windows NT version 3.51 even when the /separate switch is used. ====================================================================== Keywords : kbenv kberrmsg Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : 4.0 ============================================================================= 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. Copyright Microsoft Corporation 2001.