Cannot Run Windows Because of Video Device Conflict

• Microsoft Windows operating system versions 3.0, 3.0a

SUMMARY

When video memory has been used by another application or device driver, Microsoft Windows 3.0 doesn't start and displays the following message:

   Cannot run Windows because of video device conflict;
   Run setup again

MORE INFORMATION

It is possible to use certain areas of the upper memory area (UMA) to load device drivers high on 386 based machines. This can be done with MS-DOS version 5.0 and later, QEMM, 386MAX, and other third-party device drivers.

If a range needed for Windows graphical display is used, this error occurs. For example, a standard VGA setup requires memory ranges A000-AFFF and B800- BFFF. On some graphic adapters, the range A000-C7FF may be used.

This error occurs regardless of any EMMEXCLUDE statement in the SYSTEM.INI file.

Before attempting to use video memory ranges, be sure to create a MS-DOS bootable system disk.

For Microsoft MS-DOS version 5.0 and later, be sure not to use any video memory area necessary to run Windows. By default, EMM386.EXE does not use the range A000-BFFF. It is possible to include these memory ranges; be sure to test for compatibility when attempting to use these ranges. It may be necessary to exclude the range C000-C7FF on some video adapters by editing the CONFIG.SYS file and changing the EMM386.EXE line as follows:

   DEVICE=C:\DOS\EMM386.EXE NOEMS X=A000-C7FF

   DEVICE=C:\DOS\EMM386.EXE NOEMS X=A000-AFFF I=B000-B7FF X=B800-BFFF