SUBST, JOIN, and APPEND Commands with Windows

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Article ID: 71667 - View products that this article applies to.
This article was previously published under Q71667
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The MS-DOS commands APPEND, SUBST, and JOIN modify the way MS-DOS searches for files. This can cause problems with certain applications, including Microsoft Windows and Windows for Workgroups.


Windows 3.0

The README.TXT that comes with Microsoft Windows version 3.0 includes the following:
   Omit the APPEND, JOIN, and SUBST MS-DOS Utilities
   The MS-DOS utilities APPEND, JOIN, and SUBST can cause problems
   when you are running Windows 3.0. If you included APPEND, JOIN,
   or SUBST in your AUTOEXEC.BAT file, remove them and refrain from
   running them within Windows.
If any of these commands are in the AUTOEXEC.BAT file when Microsoft Windows 3.0 is installed, they can cause the installation to be corrupted. This can cause the unrecoverable application errors (UAEs) to continue to occur even after the APPEND, JOIN, and SUBST commands are removed from the AUTOEXEC.BAT file.

These commands can also cause intermittent UAEs if they are added after the installation of Windows. Therefore, customers who use Microsoft Windows 3.0 should be warned when these commands are added to the AUTOEXEC.BAT files.

Windows 3.1

The MS-DOS utilities APPEND, JOIN, and SUBST are listed in the [incompTSR2] section of the SETUP.INF file. If you are running these programs when you run Windows Setup, you receive the following message:
SETUP has found the programs listed below on your system. When SETUP or Windows runs with some versions of these programs, your system may fail. It is recommended that you quit Setup now and look in the file SETUP.TXT for information about using the programs with Setup or Windows. Then run Setup again.
For more information on the SUBST, JOIN, and APPEND commands, query on the following words:
subst and path and msdos


subst and join and append


Article ID: 71667 - Last Review: February 27, 2014 - Revision: 4.0
  • Microsoft MS-DOS 4.0 Standard Edition
  • Microsoft MS-DOS 5.0 Standard Edition
  • Microsoft Windows 3.0 Standard Edition
  • Microsoft Windows for Workgroups 3.1
  • Microsoft Windows for Workgroups 3.11
kbnosurvey kbarchive KB71667

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