Troubleshooting NTVDM and WOW Startup Errors
This article was previously published under Q196453
This article applies to Windows 2000. Support for Windows 2000 ends on July 13, 2010.
The Windows 2000 End-of-Support Solution Center
is a starting point for planning your migration strategy from Windows 2000. For more information see the Microsoft Support Lifecycle
This is a step-by-step troubleshooter for troubleshooting NTVDM or WOW
startup issues. Please note that Sysedit.exe is a 16-bit program available
in Windows NT available for troubleshooting these issues. If it starts up,
both the WOW and NTVDM DLLs and executables are okay and you need to
concentrate on the environmental steps below. If SYSEDIT does not start up,
try to run only the MS-DOS shell "command.com" from the command prompt.
Please note that, if SYSEDIT does not run, all of the steps below apply.
- Check the Autoexec.nt and Config.nt for anything unusual or anything
that can be commented out.
- Rename Autoexec.bat.
- Check for changes in Win.ini or System.ini, or replace by expanding the original files off of the installation media.
- Rename all other *.ini files if possible
- In the Config.nt file, allow only:
- The default entries off of the installation disk will allow
SYSEDIT to run, but other entries as outlined above may be needed for
other applications to run.
- Files has a valid range of: files = 5 to 254.
- Verify the environment variables by doing either of the following:
- Click Start, click Settings, click Control Panel, double-click
System, and then click the Environment tab. In Windows 2000, click Settings, click Control Panel, double-click System, click the Advanced tab, and then click Environment Variables.
- Run the SET command at the command prompt and check all environmental
variables for nulls, blanks, double equal sign (==) marks, or other
- Ensure that the path is the same as the default path off of the CD; that is, that there are no entries prepended to the path; if a nonstandard
entry is there, remove it.
- Check path length for lengths after expansion that are near 200
characters. Path is a combination of path in Autoexec.nt and on the
Environment tab in the System tool of Control Panel. If the path is over
100 characters, change it for testing.
- Check the following registry entries. The easiest way is to check them out is to see if they are populated first. (There are some cases where
keys or subkeys just disappear.) Then, if the keys are fully populated,
do not try to determine the correct values, just download them and load
on a test system to see if the problem can be reproduced.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows
- HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\WOW: Parameters for WOW startup
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\WOW: System.ini
- HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\IniFile\Mapping:
Mappings for Win.ini, System.ini, Winfile.ini,Progman.ini, and
- HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Environment: Environment
- Other INI settings that can be found in the registry: see pages 905
through 908 of the Windows NT Workstation 4.0 Resource Kit.
- If this does not work, you have missing or corrupted files. (More
likely, the files will be corrupted rather than missing; try to replace
Under system look for:
- Ntvdm.dll (3.1 only)
- Krnl286.exe (Windows NT 3.1 only)
- Wow32.dll (not in Windows 3.1)
Missing or corrupted DLLs second step:
If it was not one of those, you can try the DLLs under the following
Value: Known DLLs; here is the list of the DLLs, but most are in the
At this point, you may want to try the brute force method: do a parallel
installation with all updates and just copy over %SystemRoot%\System and
%SystemRoot%\System32 from the parallel installation to the new system.
Article ID: 196453 - Last Review: February 22, 2007 - Revision: 1.4
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows NT Server 4.0 Standard Edition