Cannot Use EMM386.SYS/EMM386.EXE in Standard Mode Windows 3.0

• Microsoft Windows operating system versions 3.0, 3.0a

SYMPTOMS

When you try to run Microsoft Windows version 3.0 in standard mode by typing

   win /s

   Cannot run Windows in standard mode; check to ensure you
   are not running other protected-mode software, or run in
   real mode

CAUSE

Windows cannot run in standard mode if EMM386 is active. A normal part of standard mode startup is to disable EMM386. This message occurs if you have installed EMM386.EXE for either expanded memory or UMB (upper memory block) support, which puts your computer into protected mode, thus preventing you from running Windows in standard mode.

If EMM386.EXE is installed with either the RAM or NOEMS switch to allocate UMBs, and DOS=UMB is in the CONFIG.SYS, UMB support is allocated.

If EMM386 is installed to provide expanded memory only, and expanded memory is not being used, Windows turnS off EMM386 and run normally. When EMM386 is providing UMB support or if expanded memory is being used, EMM386 can't be turned off by standard mode Windows.

To use expanded memory with an MS-DOS-based application in standard mode, you must have an expanded memory card with the associated driver.

RESOLUTION

To run successfully in standard mode, either:

• Stop using expanded memory before running Windows. If you are using MS-DOS 5.0, disable UMBs.

  -or-

• Remove EMM386.SYS or EMM386.EXE.