How to get my harddrives out of DOS compatability Mode?

Posted on 1997-10-14
Last Modified: 2013-12-16
I am running Windows 95 on a P133 machine.  I have 2 hard drives:  a WD Caviar 31000 and a Seagate ST32531A.  When I look at the System Performance tab, I have discovered these drives are running in the DOS Compatabily Mode (instead of the real mode).  The help file says that Windows was unable to recognize a real mode driver or resident program loaded in Autoexec.bat or config.sys.  However, I don't load any drivers in either of these files.

My autoexec.bat is:
set ieppp=C:\PROGRA~1\PLUS!\MICROS~1
set pctcp=C:\PROGRA~1\PLUS!\MICROS~1\pctcp.shv

My config.sys is:
DEVICE=C:\windows\HIMEM.SYS /testmem:off
device=C:\windows\EMM386.EXE ram

Since I have a total of 3 logical partitions on these 2 drives, it lists these 3 logical drives (C:, D:, E:) as having the same problem.

Does anyone have any idea how to solve this problem?  
Question by:GeneM

Accepted Solution

magigraf earned 100 total points
ID: 1751123

Just do the following:
1) Boot your system
2) At the STARTING WINDOWS 95 press F8
3) Select to start in MS-DOS mode
4) At the C:\ type the following commands
   - ren autoexec.bat autoexec.111 {enter key}
   - ren config.sys config.111 {enter key}
5) Reboot your system with CTRL+ALT+DEL
6) Let it go to windows
7) Check your performance tab, and tell me if you still see the problem.


Author Comment

ID: 1751124
I followed the recommendation of renaming the autoexec.bat and config.sys, but it did not change the situation.  

I need to add more information to my original question.  My two hard drives are the master and slave on the primary IDE connection on the motherboard.  I also have a CDROM drive attached to the secondary IDE connection.  To try to eliminate the CDROM as a factor, I took the load of the CDROM driver out of the Autoexec.bat, but the drive is still physically attached.  However, Windows Explorer does not recognize it.  Could that drive be causing a problem?

Expert Comment

ID: 1751125
The perfect settings would be:
- First hard drive on Primary Master.
- Second drive on Secondary Master.
- Cd-Rom drive on seconday Slave.

I don't thing that this would change the situation in WINDOWS, but it's worsed a try

P.S.: Don't forget to change the jumper on the SLAVE drive (second hard disk) from SLAVE position to MASTER position, since it would be master on Secondary

Could you copy the exact message in the performance tab and post it here please.

Author Comment

ID: 1751126
When I installed the second hard drive, I followed the wizzard from Seagate, which recommended I put both hard drives on the primary IDE interface.  Both hard drives are working fine (except I expect I am losing performance).

The messages are as follows:
Compatability mode paging reduces overall system performance.
Drive C:  Using MS-DOS compatability mode file system.
Drive D:  Using MS-DOS compatability mode file system.
Drive E:  Using MS-DOS compatability mode file system.

Additional information which may be of help:

In the Device Manager:
  Hard Disk Controllers:
   Standard Dual PCI IDE Controller
     Resource type                   Settings
  Input/Output Range         01F0-01F7
  Input/Output Range         03F6-03F6
  Interupt Request               14
  Input/Output Range          F000-F007
  Input/Output Range          F008-F00F

Thank you for your interest in this problem.

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Expert Comment

ID: 1751127

You have quite some reading to do here, but I felt obligated to post these information to you. (you could also copy it and print it for futur reference)


The Performance tab in System properties shows that one or more of the hard disks in your computer is using MS-DOS Compatibility mode. MS-DOS compatibility mode may be in use for either the file system or for virtual memory. You may receive the following message:

   Compatibility Mode Paging reduces overall system performance


MS-DOS Compatibility mode may be in use for any of the following reasons:

  •An "unsafe" device driver, memory-resident program, or virus    hooked the INT21h or INT13h chain before Windows 95 loaded.
  •The hard disk controller in your computer was not detected by    Windows 95.
  •The hard disk controller was removed from the current    configuration in Device Manager. •There is a resource conflict    between the hard disk controller and another hardware device.   •The Windows 95 protected-mode driver is missing or damaged.   •The Windows 95 32-bit protected-mode disk drivers detected an    unsupportable configuration or incompatible hardware.


To correct the problem, follow these steps:

1.Use the Performance tab in System properties to identify which drive is using MS-DOS Compatibility mode and why.

NOTE: Floppy disk drives and CD-ROM drives operating in MS-DOS Compatibility mode cause the Performance tab to display the message "Some drives are using MS-DOS compatibility" for the file system, but this article applies only to troubleshooting hard disks operating in MS-DOS Compatibility mode.

a. If the driver name listed as causing MS-DOS Compatibility mode
is MBRINT13.SYS, your computer may be infected with a boot-sector
virus, or you are running real-mode geometry translation software
(for an IDE hard disk with more than 1024 cylinders) that is not
compatible with Windows 95 protected-mode disk drivers.

 For information about real-mode geometry translation software that is compatible with Windows 95 protected-mode disk drivers, please see the following article in the Microsoft Knowledge Base:

         ARTICLE-ID: Q126855
         TITLE     : Windows 95 Support for Large IDE Hard Disks

Disk Manager 6.03 is supported in protected mode on hard disks on
the primary IDE channel and when DriveSpace disk compression is not installed. For drives on the secondary IDE channel, Disk Manager 7.0 or later is required. When using the DriveSpace compression software that is included with Microsoft Windows 95 and Microsoft Plus!, Disk Manager 7.04 or later must be used. For more information, please see the following article in the Microsoft Knowledge Base:
         ARTICLE ID: Q126855
         TITLE     : Windows 95 Support for Large IDE Hard Disks

For information about detecting and removing boot-sector viruses,
please see the following articles in the Microsoft Knowledge Base:
         ARTICLE-ID: Q82923
         TITLE     : Methods to Detect a Boot-Sector Virus

         ARTICLE-ID: Q129972
         TITLE     : Description of Computer Viruses

         ARTICLE-ID: Q49500
         TITLE     : List of Anti-Virus Software Vendors

b. If a driver that is listed in the CONFIG.SYS file is named, contact the driver's manufacturer to determine whether there is a version of the driver that allows protected-mode access in Windows 95.

If no driver is listed on the Performance tab, continue with Step # 2.

2.Check to make sure that the hard disk controller is listed in Device Manager. If it is not listed, install it with the Add New Hardware Wizard. If the Wizard does not detect the controller, run the Wizard again but do not let the Wizard detect the hardware in your computer. Instead, select the controller from the hardware list. If the controller is not listed, contact the manufacturer of the hard disk controller to determine whether there is a Windows 95 protected-mode disk driver or a Windows 3.1 32-bit disk access (FastDisk) driver available.

NOTE: If the hard disk controller is listed in Device Manager but has a red X over it, it has been removed from the current hardware profile. Click Properties for the controller in Device Manager and then click the check box corresponding to the current hardware profile under Device Usage.

3.If the hard disk controller is listed in Device Manager but has a yellow exclamation point over it, there is an IRQ, I/O, DMA, or RAM address conflict with another device, the protected-mode driver is missing or damaged, or the "Disable all 32-bit protected-mode disk drivers" check box is selected in File System properties.

a. Check to make sure that the "Disable all 32-bit protected-mode disk drivers" check box has not been selected on the Troubleshooting tab in File System properties. To access this tab, double-click System in Control Panel, click the Performance tab, and then click File System.

b. Resolve any resource (IRQ, I/O, DMA, or RAM address) conflicts
with other devices. Consult the controller's documentation for
information about resource usage and changing resource usage.

c. Check to make sure that the protected-mode driver is in the
Windows\SYSTEM\IOSUBSYS directory and is loading properly. To
determine which driver is providing 32-bit disk access, click
Properties for the controller in Device Manager and click the Driver tab to see which driver files are associated with the controller.
NOTE: If you are using an IDE, EIDE, or ESDI hard disk controller, the Driver tab may not be present when you click Properties for the controller in Device Manager. Unless you are using a third-party driver, Esdi_506.pdr is the protected-mode driver that is used to provide 32-bit disk access for these controllers.

Restart Windows 95 and press F8 at the "Starting Windows 95"
message. Select a Logged (/BOOTLOG.TXT) start. Examine the
just-created BOOTLOG.TXT file to determine if the driver listed
above is loading properly.
If the BOOTLOG.TXT file shows an "Init Failure" or "Load Failure"
message for the driver listed above, proceed with step D. If the
BOOTLOG.TXT file shows an "INITCOMPLETESUCCESS" message for the
drive listed above, examine the IOS.LOG file.

Windows 95 creates an IOS.LOG file in the Windows directory if any drives are using MS-DOS Compatibility mode. The first few lines of the IOS.LOG file may contain information describing why the protected-mode disk driver failed to load. Please have this
information available if you contact Microsoft Product Support
Services about this problem.

d. Make sure the protected-mode driver is not damaged. For all ESDI and IDE drives, Windows 95 uses ESDI_506.PDR in the IOSUBSYS directory to provide 32-bit disk access. For SCSI controllers, Windows 95 uses SCSIPORT.PDR and a "mini-port" (.MPD) driver to provide 32-bit disk access. Manually extract the appropriate .PDR or .MPD files from the Windows 95 disks or CD-ROM, or run Setup and choose the Verify option.

4.Check to see if the Mh32bit.386 driver is being loaded in the System.ini file. Check for a line that reads
This driver is installed by MicroHouse EZ-Drive software, and is not compatible with the Windows 95 protected-mode disk drivers. This driver is not removed by Windows 95 Setup.

5.Contact the hard disk controller's manufacturer for information about Windows 95 compatibility. You may be able to get protected-mode, 32-bit disk access in Windows 95 by using one of the following methods:
  - Disable any enhanced features (such as caching, fast or turbo     mode, reduced data transfer rates, and so on) on the         controller (SCSI, IDE, or ESDI) or system BIOS (IDE only).

  - obtain a protected-mode Windows 95 disk driver, or Windows       3.1 FastDisk driver for the controller.


A real-mode driver is "safe" if its functionality does not exceed the functionality of the corresponding Windows 95 protected-mode driver. If a real-mode driver is safe, the protected-mode driver can take over all I/O operations for the corresponding device. Otherwise, Windows 95 routes all I/O operations through the real-mode driver.

An example of an unsafe driver is a real-mode IDE/ESDI driver that uses dynamic encryption for security reasons. Since Windows 95 does not provide encryption, Windows 95 does not allow the protected-mode IDE/ESDI driver to take over the real-mode driver. Any real-mode driver with functionality on the following list is considered unsafe:

 •Data compression that is not compatible with DoubleSpace
 •Data encryption
 •Disk mirroring
 •Bad sector mapping
 •Fault tolerance (for example, maintenance of ECC correction on   a separate disk)
 •Vendor-specific IOCTLs •Microsoft-defined IOCTLs with   vendor-extended features

The safe driver list (the IOS.INI file) is a Windows 95-maintained list of safe drivers. Each entry in the list identifies a driver or TSR that Windows 95 can take over with the corresponding protected-mode driver. The safe driver list includes the name of the driver or TSR. This name should be the same as the name in the CONFIG.SYS or AUTOEXEC.BAT file.

Windows 95 does not store the version number of the driver or TSR in the list, so it is the responsibility of the vendor to change the name of the driver if a future version of the driver is enhanced in a manner that makes the driver unsafe.

By default, the following drivers are considered safe:

 •MS-DOS 5.0-compatible real-mode block device drivers
 •INT 13 monitors (hooks INT 13 for monitoring INT 13 I/O but   does not access the hardware directly or modify the I/O buffer)  •INT 13 hooker (hooks INT 13 for altering INT 13 I/O but does   not access the hardware directly)
 •INT 13 driver (provides INT 13 functionality and directly   accesses the hardware)
 •ASPI Manager (implements ASPI for MS-DOS specification)
  CAM Manager (implements MS-DOS CAM specification)

NOTE: If the real-mode driver you are using has better performance or provides some functions that are not be present in the Windows 95 protected-mode driver, the driver's vendor should remove the driver from the safe driver list. The system will use real mode to access the drive. If the real-mode driver you are using can be safely taken over by protected-mode drivers, the driver's vendor can add that driver to the safe driver list.

Disk Manager is manufactured by OnTrack Computer Systems, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

EZ-Drive is manufactured by Micro House, a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.

I hope you found some usefull answers here or keep posting and I'll help you out.

Expert Comment

ID: 1751128
Very good answer. I would check the VIRUS angle of the matter.

Author Comment

ID: 1751129

Thanks to your very long recommendation, I determined that I had a damaged protected-mode driver.  I reinstalled Win95 with the verify option, and the problem was solved.

You have earned 100 points!


Expert Comment

ID: 1751130
You're welcome, I can now rest that you are up and running.

Expert Comment

ID: 1751131
MY FIRST EXPERIENCE WITH DOS COMPATABILITY MODE was the first time I added a second hard drive to a system. At that time I thought I'd found a terrific easy fix to what, at that time, (over 2 years ago), was not as well understood as it is now.
The DCM was only on the partitions of the new drive. I discovered that upon using DriveSpace3 to compress the last partition on the first drive, and then the last partition on the second disk, all the partitions in the middle fell nicely into line. I even tested it. I REMOVED the compressed drives and sure enough, DCM returned to the second disk and all it's parts.
So I put the compressed drives BACK and again, WAH-LAH!
But, never satisfied, now I'm thinking, hey, WHAT IF I DON'T WANT NO STEEEENKING COMPRESSED DRIVES? So I performed a final test, I again removed the compressed drives, only this time when it asked about removing the compressed drive driver from memory, I SAID NO. LEAVE IT. and, guess what? NO DCM.
    Well here I am again 2 years later only this time DriveSpace3 ain't doin' it! (?) Why not? Same situation. Only the drives on the  new, second hard drive are effected. But there is a difference.
The first time:
Drive One; Primary Master
Drive Two; Primary Slave
CD ROM, I don't remember for sure, but it must have been off the floppy cable because the Seconday IDE was not in use. There was only ONE IDE ribbon cable. Anyway it worked.

This, time, different computer, different BIOS, I had trouble getting the CD ROM to run that same way, the first option to be successful was as a Primary Slave, so, this time the BOIS setup:

Drive One: Primary Master
CD ROM  : Primary Slave
Drive Two: Secondary Master

Notice the ORDER in which they a listed. Remember, only the partitions on DRIVE TWO are "DCM".  Something is RIGHT with Drive One that isn't CARRYING OVER successfully to Drive Two.  Obviously my "protected-mode driver was not damaged because it was working just fine on Drive One.

In the above configuration, (in laymans language), the CD ROM acts as a 'barrier' preventing certian 'serial communication' between the hard drives from being completed CORRECTLY, (controler-driver-wise). So, here's what I'm going to do, (current "DCM" condition is still present)     Based partly on previous comments here, (above),

Step One: Reconfigure the Bios Setup as follows:

Disk One: Primary Master
Disk Two: Secondary Master
CD Rom : Secondary Slave

then (If still DCM),

Step Two: via System Props, Device Manager,  REMOVE all HD controlers and let Windows reinstall them.

If that dosn't work, then try,

Disk One: Primary Master
Disk Two: Primary Slave
CD ROM: Secondary Master
         Remove & Reinstall HD Controlers

Then if it still dosn't work, last but not least,


For those who don't know, NORMALLY you can reinstall Win95 without losing your original Windows customizations. (depending on why you're reinstaling and/or how badly trashed the original copy was).....  

Am I on?  I'll let you know....   comments?  Points for speaking plain English?

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