MSDOS.SYS help and information

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 Windows95 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. This is to give 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 within the time (in seconds) set as the value of BootMenuDelay. Default is 1 which is 'Normal Windows'. All Win9x 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 will enable 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 Windows95.
LoadTop= Load COMMAND.COM or DRVSPACE.BIN at top of conventional memory.
Logo= Enables display of the Windows95 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.