Windowed MS-DOS Apps Revert to Full Screen in Windows


While running an MS-DOS application in a window, Microsoft Windows may switch it to full screen if an MS-DOS critical error occurs. Typically, the critical error will be a disk error, but there are other causes as well.

The common critical MS-DOS errors are:

  • attempting to access a floppy drive with no disk
  • attempting to write a file to a write-protected floppy disk
  • attempting to access an unformatted floppy disk
When an MS-DOS critical error occurs, MS-DOS is unstable until the critical error is resolved. To maximize stability, Windows switches the application to full-screen text mode. This is by design and there is no workaround. Press ALT+ENTER, after the error is resolved, to switch the MS-DOS application back to the windowed display mode.

More Information

Switching Between Full Screen and Windowed Display Modes

The "windowed" display mode of MS-DOS applications is only available in 386 enhanced mode. There are three actions that can be performed to run an MS-DOS application in a window or full screen:

  1. Select the desired mode in the PIF Editor.
  2. Press ALT+ENTER to toggle between the two modes.
  3. Select the desired mode from the MS-DOS application's system menu:

    1. Start the MS-DOS application in question.
    2. Press ALT+SPACEBAR to display the system menu.
    3. Select Settings (press T).
    4. Select Windowed (press W).
    5. Press ENTER.

MS-DOS Int 24H Critical Errors

The critical error handler is a function of interrupt 24H. A complete listing of the MS-DOS Int 24H critical errors are listed below.

Error Code
Hex Dec Description

00H 0 Write-protect error
01H 1 Unknown unit (invalid drive number)
02H 2 Drive not ready (no disk or driver door open)
03H 3 Unknown command requested
04H 4 Data error (CRC)
05H 5 Bad request structure length
06H 6 Seek error; move to requested cylinder failed
07H 7 Unknown disk format
08H 8 Sector not found
09H 9 Printer out of paper
0AH 10 Write fault
0BH 11 Read fault
0CH 12 General, nonspecific error
0FH 15 Invalid disk change (MS-DOS version 3.0 or later)

ID do Artigo: 71211 - Última Revisão: 7 de jul de 2005 - Revisão: 1