Troubleshooting NTVDM and WOW Startup Errors
This article was previously published under Q220155
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This is a step-by-step troubleshooting guide for examining Windows NT Virtual DOS Machine (NTVDM) or Windows on Windows startup issues.
To begin troubleshooting, determine whether you are dealing with problems in the NTVDM or problems in both the NTVDM and the Windows on Windows subsystem.
NOTE: Sysedit.exe is a 16-bit program available within Windows NT for troubleshooting these issues.
Problem DiagnosisTo diagnose your problem:
- Start System Configuration Editor (Sysedit.exe).
If this program starts correctly, then there is not an issue with either the NTVDM or the Windows on Windows subsystem. The problem then is with your program not Windows NT. If the program is an older version and requires EMS memory, you must configure it. For more information, please see the following Microsoft Knowledge Base articles:Q99279 MS-DOS-Based Application and Command PromptsIf the program requires more convential memory than is available, please see the following Microsoft Knowledge Base article:
Q196875 Error When EMS Memory Is Configured for MS-DOS App in .pif FileQ99363 Increasing Memory for MS-DOS-Based ApplicationsHowever, if System Configuration Editor does not start correctly, then you do not know where the problem lies. Because the problem could be with either Windows on Windows or NTVDM, go to step 2. If troubleshooting determines that the problem is with the Windows on Windows subsystem, then all of the steps listed below in the Troubleshooting section below apply.
- Run the MS-DOS shell (running the Command.com command from the MS-DOS command prompt).
If this program starts, then run the Edit.com command, then you know that NTVDM works. If the shell does not start, then all of the troubleshooting steps below apply (except steps 3 and 4).
- Check and delete the default NTVDM. Run the Sysedit.exe command at a command prompt.
NOTE: If for any reason your computer does not pass the previously mentioned test, then repeat the entire procedure above after you complete the next three steps.
- Start Task Manager, click the Processes tab, and then click the Image name column.
- Look for the Image name ntvdm, and then stop the process if you find it in the list. If you do not find it in the list, skip the next step.
- Repeat the procedure outlined in steps 2 and 3 above.
TroubleshootingPlease repeat the following steps in the order they appear to troubleshoot issues with either the NTVDM or Windows on Windows subsystems.
Please note that steps three and four apply only to the situation where the Windows on Windows subsystem does not start.
- Check the Autoexec.nt and Config.nt files 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 the following values only:
dos=high, umb device=%SystemRoot%\System32\Himem.sys files=60 shell=%SystemRoot%\System32\Command.com /e:4096NOTE: The default entries off of the installation disk will allow SYSEDIT to run, but other entries as outlined above may be needed for other programs to run. Also, files has a valid range of 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.
- Run the set command at the command prompt and check all environmental variables for nulls, blanks, double equal sign (==) marks, or other unknown entries.
- 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. Add only the entries needed for your one program and the defaults.
- 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.
- If this does not work, you have missing or corrupted files. (More likely, the files will be corrupted rather than missing; try to replace these first.)
Under the System32 folder look for:
- Ntvdm.dll (3.1 only)
- Krnl286.exe (Windows NT 3.1 only)
- Wow32.dll (not in Windows 3.1)
Article ID: 220155 - Last Review: 12/05/2015 13:07:25 - Revision: 2.1
Microsoft Windows NT Server 4.0, Terminal Server Edition, Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Workstation 4.0 Developer Edition
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