Cannot Switch Away from Full-Screen MS-DOS-Based Program

When you run an MS-DOS-based program in a full screen, you may be unable to switch to another program using the ALT+TAB or CTRL+ESC key combinations. When you try to switch to another program, the computer may beep. This problem can occur with the following types of MS-DOS-based programs:

• Programs that use a high-resolution graphics mode (such as SVGA or VESA modes).
• Programs that use a high-resolution text mode.
• Hard disk tools such as disk defragmenter or undelete tools.

If you are running an MS-DOS-based program that uses a high-resolution graphics or text mode, the problem occurs because the program is using a video mode that the virtual display driver cannot save and restore. If you switched to another program, you would not be able to switch back because the virtual display driver could not restore the screen.

If you are running a hard disk tool, the problem occurs because the tool has taken an exclusive-access lock on one or more of the drives in the computer. When a drive has been locked by an MS-DOS-based program, Windows does not switch away from that program.

If you are running an MS-DOS-based program that uses a high-resolution graphics or text mode, you may be able to work around the problem by configuring the program to use a lower resolution. For information about how to do so, please consult the program's documentation or manufacturer.

If you are running a hard disk tool, you cannot switch programs until you quit the tool. Windows does not switch away from an MS-DOS-based program that has locked a drive.