MSDOS.SYS help and information

Updated: 05/21/2018 by Computer Hope

The MSDOS.SYS file is a hidden, system, read-only file created on the root of the boot drive. There are several configurations that can be changed using this file. To edit the file, first from C:\> Type attrib -h -s -r MSDOS.SYS

As always, make a backup copy in case you mistakenly cause an issue when trying to edit this file. To edit this file, type edit msdos.sys.

Most values in the MSDOS.SYS are either 0 or 1, which is off or on.

Entry Description
- [Paths] section -
HostWinBootDrv=C Location of the boot drive root directory.
WinBootDir= Location of necessary startup files.
WinDir= Location of the Windows 95 directory.
- [Options] Section -
AutoScan= Allows Windows 95 OSR2 and above to scandisk the hard disk drive if the computer was improperly shutdown. The default is 1. Setting the value to 0 causes the computer to not scandisk the hard disk drive. Setting the value to 1 prompts the user for scanning the hard disk drive (scan begins if no input for 60 seconds). Setting the value to 2 allows for automatic scanning (no prompt).
BootConfig= Allow processing of the current boot setup. Setting the value to 0 performs and alternate boot setup. Setting the value to 1 performs the current boot setup.
BootMulti= Allows booting to previous operation system. The default is 0. Setting this to 1 allows you to press F4 to start your previous version of DOS or F8 to use the Startup Menu.
BootDelay=n This sets the initial delay to n seconds before starting Windows which gives you enough time to press the F4 or F8 keys. The default is 2 seconds.
BootMenu= Enables the automatic display of the Windows Startup Menu. The default is 0 so that you need to press F8 on bootup to see the Startup Menu. Changing it to 1 will always bring up the Startup Menu.
BootMenuDefault=# The corresponding Boot Menu option that will be used if there is no user intervention in the time (in seconds) set as the value of BootMenuDelay. Default is 1, which is 'Normal Windows'. All Windows 9x Boot options are given below.

1 = Normal Windows.
2 = Logged (create c:\bootlog.txt while booting).
3 = Safe Mode.
4 = Safe mode with network support (if present, otherwise it shouldn't show).
5 = Step-by-step Confirmation (prompt at each boot step for choice).
6 = Command prompt only.
7 = Safe mode command prompt only.
8 = Previous version of MS-DOS (if present).

BootMenuDelay=# This sets the number of seconds to show the Windows Startup Menu before running the default menu item (see previous item). The default is 30 seconds.
BootSafe= Force Safe Mode startup. The default is 0. Setting to 0 will disable this feature, 1 enables it.
BootKeys= This enables the startup option keys (F5, F6, F8). The default is 1. Setting this to 0 prevents any startup keys from functioning.
BootGUI= This enables the automatic graphical startup into Windows. The default is 1 setting this to 0 will boot you to a DOS prompt. You can then type "WIN" to start Windows 95.
LoadTop= Load COMMAND.COM or DRVSPACE.BIN at top of conventional memory.
Logo= Enables display of the Windows 95 animated logo. The default is 1.
BootWarn= Enables starting in Safe Mode without a warning. The default is 1.
DblSpace= Load DBLSPACE.BIN module (if present). The default is 1.
DoubleBuffer= Enables loading of a double-buffering driver for a SCSI controller, if required. The default setting is 0
DisableLog= Create BOOTLOG.TXT upon bootup. The default is 1.
DrvSpace= Load DRVSPACE.BIN module (if present). The default is 1.
Network= Enables Safe Mode with Networking as a menu option. The default is 1 for computers with a network installed.
SystemReg= Scan System Registry modules upon startup. Set value to 1 to enable, 0 to disable.
WinVer= Display Windows version. Set value to 1 to enable display Windows version, 0 to disable.

Example of msdos.sys


;The following lines are required for compatibility with other programs.
;Do not remove them (MSDOS.SYS needs to be >1024 bytes).

Additional information

  • See our attrib and edit command pages for further information on each of these commands.