Windows/386 2.1x Compatibility with MS-DOS 5.0 or Later (73829)

The information in this article applies to:
    Microsoft MS-DOS operating system 5.0
    Microsoft MS-DOS operating system 5.0a
    Microsoft MS-DOS operating system 6.0

This article was previously published under Q73829


Windows 386 versions 2.1 and 2.11 cannot run when EMM386.EXE from MS-DOS 5.0 or later is loaded in the CONFIG.SYS file. Attempting to use this configuration results in the following error message:

Error: Protected mode software already installed
This problem occurs regardless of which switches are used with EMM386.EXE. To run Windows/386 2.1x, you cannot use EMM386.EXE to emulate expanded memory or load drivers high.


Other device drivers from the Microsoft MS-DOS 5.0 Upgrade to be aware of are listed in the README.TXT file section 4.5.

The following is an excerpt from the README.TXT file:

4.5 "High Memory Area in Use" Message (Windows/386 2.1)

You cannot run Windows/386 2.1 when MS-DOS 5.0 is loaded into the high memory area. Also, the MS-DOS 5.0 versions of SMARTDRV.SYS and RAMDRIVE.SYS are not compatible with Windows/386 2.1. To run Windows/386 2.1 with MS-DOS 5.0, use the versions of SMARTDRV.SYS and RAMDRIVE.SYS that came with Windows and remove the DOS=HIGH command, if any, from your CONFIG.SYS file.

Modification Type: Major Last Reviewed: 10/16/2003
Keywords: KB73829