MS-DOS Compatibility Mode Problems with PCI IDE Controllers

Taken from Microsoft article # Q151911

The information in this article applies to:
IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

If your computer contains a Peripheral Component Interconnect (PCI) Integrated Drive Electronics (IDE) hard disk controller that employs serialization between the two IDE channels, you may experience the following behaviors:

If you uninstall and then reinstall the hard disk controller, this behavior is not resolved.

CAUSE

This behavior can occur if the protected-mode driver for the hard disk controller is not properly initialized when you start Windows. When this occurs, a NOIDE value is placed in the registry which prevents Windows from making future attempts to initialize the protected-mode driver.

RESOLUTION

NOTE: The purpose of the registry value that is mentioned in this section is to prevent damaged data. Before you modify this registry value, Microsoft recommends that you perform the troubleshooting steps in the following Microsoft Knowledge Base article:

Q130179 Troubleshooting MS-DOS Compatibility Mode on Hard Disks

All Versions

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT or Windows 2000, you should also update your Emergency Repair Disk (ERD).

To cause Windows to attempt to reinitialize the protected-mode IDE driver:
  1. Click Start, click Run, type regedit in the Open box, and then press ENTER.

  2. Locate and click the following registry key:

    HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\IOS
  3. In the right pane, right-click the NOIDE value, and then click Delete.

  4. Quit Registry Editor.

After you update the registry, restart Windows. Windows attempts to initialize the protected-mode driver for the controller. If Windows can initialize the protected-mode driver for the controller, the file system and virtual memory operate in 32-bit mode and Device Manager does not display an exclamation point in a yellow circle for the IDE channels.

If the protected-mode driver is not initialized properly, you receive an error message and the NOIDE value is re-created. Windows uses the MS-DOS Compatibility mode file system the next time that you start the computer.

Windows 98 Only

If you are running Windows 98 on your computer, locate the Tools\Mtsutil folder on the Windows 98 CD-ROM, right-click the Noide.inf file, and then click Install. When you do this, the NOIDE value is deleted if it exists. After you use this file, restart your computer.

MORE INFORMATION

This problem can occur if your computer has an IDE controller that requires serialization between the primary and secondary IDE channels. The protected-mode drivers for these IDE controllers may not be initialized if one of the following situations occurs:

The Windows device drivers for the following controllers may cause this behavior: Other PCI IDE controllers that use serialization between the IDE channels may also cause this behavior.

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