Microsoft KB Archive/926171

Knowledge Base

You cannot install a device that requires the Mf.sys device driver in Windows Vista

Article ID: 926171

Article Last Modified on 12/4/2007

---

APPLIES TO

• Windows Vista Business
• Windows Vista Enterprise
• Windows Vista Home Basic
• Windows Vista Home Premium
• Windows Vista Ultimate
• Windows Vista Enterprise 64-bit Edition
• Windows Vista Home Basic 64-bit Edition
• Windows Vista Home Premium 64-bit Edition
• Windows Vista Ultimate 64-bit Edition
• Windows Vista Business 64-bit Edition

---

SYMPTOMS

When you try to install a device that requires the Mf.sys device driver on a computer that is running Windows Vista, you cannot install the device. Additionally, after you try to install the device, service keys that are related to the device are not in the Windows registry.

CAUSE

By default, the Mf.sys device driver is not installed in Windows Vista. By default, this device driver is installed in earlier versions of Windows. Microsoft made this change in Windows Vista because the Mf.sys device driver is rarely used.

RESOLUTION

To resolve this problem, install the Mf.sys device driver. To do this, follow these steps:

1. In Windows Explorer, open the %systemroot%\System32\DriverStore\FileRepository folder.
2. Locate and then double-click the Mf.inf_Identifier folder.
   
   Note In this folder name, Identifier may resemble the value "dcf62a9a."
3. Right-click the Mf.sys file, and then click Copy.
4. In Windows Explorer, open the %systemroot%\System32\Drivers folder.
5. Click Organize, and then click Paste.
6. In the Destination Folder Access Denied dialog box, click Continue.
7. In the User Account Control dialog box, click Continue.
8. Make sure that the .inf file for the device contains a DDInstall section and a DDInstall.Services section. Make sure that these sections appear in a format that resembles the following:

   [install-section-name]
   Include=mf.inf
   Needs=MFINSTALL.mf

   [install-section-name.Services]
   Include=mf.inf
   Needs=MFINSTALL.mf.Services

   Note The first section copies the most recent version of the Mf.sys file. The second section installs the service.

Keywords: kbtshoot kbprb kbexpertiseadvanced kbexpertiseinter KB926171

---

Send feedback to Microsoft

© Microsoft Corporation. All rights reserved.