Err: Win16 Subsystem Unable to Enter Protected Mode (150420)


The information in this article applies to:

  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
This article was previously published under Q150420

SYMPTOMS

When you attempt to access a 16-bit application from Windows NT and are using Fprot.exe, the following error message is displayed:
The Win16 Subsystem was unable to enter Protected Mode, DOSX.EXE must be in your AUTOEXEC.NT and present in your PATH.

CAUSE

Fprot.exe inadvertently changes the file's attributes to read/hidden/system attributes. The following may be affected:
  • WINNTxx
  • WINNTxx\SYSTEM
  • WINNTxx\SYSTEM32
  • WINNTxx\SYSTEM32\DRIVERS
  • WINNTxx\SYSTEM32\REPAIR

RESOLUTION

Compare the damaged system with a fresh install of NT on a second computer and reset the attributes with either the "attrib" command or File Manager.

MORE INFORMATION

ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [[drive:] [path] filename]
[/S]

+   Sets an attribute.
-   Clears an attribute.
R   Read-only file attribute.
A   Archive file attribute.
S   System file attribute.
H   Hidden file attribute.
/S  Processes files in all directories in the specified path.
Modification Type:MajorLast Reviewed:12/16/2003
Keywords:KB150420
©2003 Microsoft Corporation. All rights reserved.