Programs with Reserved Windows Filenames May Not Run

 Last reviewed: November 23, 1994
Article ID: Q86181
The information in this article applies to:
  • Microsoft Windows operating system versions 3.1, 3.11

SUMMARY

In Microsoft Windows version 3.1, if a program's executable filename is a name that is reserved by Windows, the file will not run. There is no error message associated with this behavior.

In addition, if a program's executable file has a name that is already running in memory and the program running in memory can only occur once, the duplicate program will:

  • not execute
  • not return an error message
  • may execute the duplicate program

MORE INFORMATION

This occurs because when Windows gets the request to run a new program, it checks for another occurrence of this program in memory. It does this by looking at the first eight characters of the filename and then comparing the information to the programs in memory.

If Windows finds another version of this program in memory, it sends this new instance to the currently running program. It is then up to this program whether or not to execute a new instance. If the program is set up to make itself active, then it will become active. If the program is reserved by Windows or its operating system, such as KERNEL.EXE, then the new program will not execute.

Unusable executable filenames: 

   CGA40WOA.EXE
   COMM.EXE
   COMMDLG.EXE
   GDI.EXE
   DISPLAY.EXE
   DOSAPP.EXE
   FIXFONTS.EXE
   FONTS.EXE
   KERNEL.EXE
   KEYBOARD.EXE
   MMSYSTEM.EXE
   MOUSE.EXE
   PROGMAN.EXE
   SHELL.EXE
   USER.EXE
There may be other executable filenames that cannot be duplicated, depending on the configuration and third-party applications.

KBCategory: kbother kbdisplay kbprb
KBSubcategory: win31
Additional reference words: 3.10 3.11 file name

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Last reviewed: November 23, 1994
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