Invalid settings in the MSDOS.SYS file??

Posted on 2001-07-31
Last Modified: 2008-02-01
When I starting up machine I get this message from DOS black screen:

Invalid settings in the MSDOS.SYS file: ORIG_DIAG_BOOTMENU=<NIL>

This machine is unstable. Sometimes I can proceede and boot to Windows 98 but another time it hangs at Windows 98 screen so I have to power off and go to Safe Mode.

This machine uses 3 serial ports.

What could be wrong and how I could go about fixing this problem?
(I am not knowledgeable in DOS)

Thanks for help.
Question by:howei
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Expert Comment

ID: 6339596
okay you can obtain a bootdisk from this site If you are runnig win98, obtain only win98 bootdisk.

Change the boot sequence to a: . Now after booting for the bootdisk type sys c: to copy back the system file

Hoep this help



Accepted Solution

rin1010 earned 50 total points
ID: 6341924


That line is used in the MSDOS.SYS file for diagnosing startup problems.
It's typically appended to MSDOS.SYS by the System Configuration Utility
(MSCONFIG.EXE) when you've chosen the "Diagnostic Startup" option.
You can run the MSCONFIG utility to try correcting it.
One way to launch it is to click "Start" then choose "Run" and type MSCONFIG ...

Once it's open, on the "General" Tab make sure "Normal Startup" is selected.
If "Normal Startup" is already checked, choose "Diagnostic Startup"
and then click "Apply"... Now re-select "Normal Startup" and click "Apply" again
and the line should be removed from MSDOS.SYS ...
Restart your computer and see if the error is fixed.

The MSDOS.SYS file is a text file having settings for starting Windows
and if necessary can be edited manually, e.g. in Notepad under Windows
or using MS-DOS Edit in either Windows or DOS mode.

MSDOS.SYS is a "Hidden" file, so to find it in Windows you'll need the
"Show All Files" option selected on the "View" Tab under "Folder Options"
(from Explorer's 'View' menu)...

But you can also open MSDOS.SYS in Notepad without changing its attributes...
Launch Notepad and choose "Open" from the "File" menu...
In the "FileName" field type C:\MSDOS.SYS and click "Open"...

Once you've opened MSDOS.SYS for editing, remove the line causing the error...
If there's also a line reading BootMenu=1 change the 1 to 0 (zero)
or remove the line completely. An alternative to removing a line in MSDOS.SYS
is to place a semicolon ( ; ) before a line, which tells Windows to ignore that line, like this:


Some other things to note here... Make a backup copy of MSDOS.SYS before editing it.
Also, if you have trouble saving the edited file, its Read-Only attribute may be set
and will need to be cleared.

As your first step is to "unhide" the MSDOS.SYS file, the simplest method is
to do it all from a command prompt. You can clear its attributes and back it up,
either in DOS mode or from a DOS box in Windows, using the methods below...

Open a DOS Prompt window (or start in DOS mode) and get to a command prompt...
These examples use the complete path of C:\MSDOS.SYS or you can first type CD\
and change to the root directory... (To effect changes, be sure you're working with the
correct copy of MSDOS.SYS ... If you're using DriveSpace, the correct copy
could reside on the Host drive, typically the root of H: drive.)

Once you're at a command prompt, clear the MSDOS.SYS file attributes by typing:


Then make a backup copy of MSDOS.SYS by typing:


If in Windows, you can now open MSDOS.SYS in Notepad
from the command prompt by typing:

Notepad C:\MSDOS.SYS

In DOS mode use EDIT.COM ... same as above but type:    EDIT C:\MSDOS.SYS

Otherwise, just launch Notepad, browse to the root directory (C:\) and open MSDOS.SYS ...
Once it's open, edit the file as indicated above, then save it and restart your computer.

Regarding your comment that it "hangs at Windows 98 screen so I have to power off
and go to Safe Mode." are a couple of tips; If you're choosing "Safe Mode"
from the "Startup Menu"- choose "Safe Mode Command Prompt Only" instead.
This won't fix anything, but once at the command prompt you can reboot
to "Normal" Windows and eliminate waiting while it starts in Safe Mode.
Also, when it "hangs at Windows 98 screen" press the ESC key
and see if there are other error messages behind the logo.

Beware that restoring the system files from a boot disk using the SYS command
can overwrite your current copy with a generic MSDOS.SYS file having no settings,
causing Windows to start with the defaults, which may not be appropriate for your machine.

Post back if you need more info on editing MSDOS.SYS or the attributes thing.
If you want help ensuring the format is correct, paste a copy of your
MSDOS.SYS contents here for suggestions as to the appropriate settings,
and if so, please indicate whether you're running Windows 98 or 98SE ...

Expert Comment

ID: 6352417
1. Remove the read only and hidden attributes on MSDOS.SYS in the root directory on your windows drive.
2. Make a backup copy of MSDOS.SYS to MSDOS.OLD.
3. Edit MSDOS.SYS with notepad
4. Find or add a line containing the appropriate settings. These are the recommended values
     a) BootDelay=0, removes the two second delay when the PC starts.
     b) AutoScan=2, automatically runs scandisk when Windows does not shutdown properly.       Only available in Windows 95B(4.00.1111) or later.
     c) DblSpace=0 (do not set to 0 if you are using disk compression), disables automatic loading of the
     DoubleSpace disk compression driver.
     d) DrvSpace=0 (do not set to 0 if you are using disk compression), disables the automatic loading of the
     DriveSpace disk compression driver.
5. Save MSDOS.SYS.
6. The new settings will take effect when you restart your PC.

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Expert Comment

ID: 6362211
Also, you might want to make sure there is NOT a line like this in MSDOS.SYS


If it is there, you might need to take it out; I found that even if BootMenu=0, sometimes Windows will display the boot menu BUT will not let you select any of the menu options.

You might need to "sys c:" after taking out this line. Of course, boot your computer from floppy.

Expert Comment

ID: 6548562
try to not remove too much of that file, some older code needs it to have a length, but since it is solely for DOS use, it (file) is not always required.

Expert Comment

ID: 6615114

Expert Comment

ID: 6928884
From my limited knowledge, Windows 98 has an option to dual boot.  But, when you boot into MS-DOS once, you won't be able to boot into Windows 98 again.  This is Microsoft "feature" of Windows 98.  If you really need dual boot, I will recommend to use BootMagic or other boot manager software.

Expert Comment

ID: 7060986

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Expert Comment

ID: 7069812
Thanks, finalized by EE Moderator.

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