Cleaning Up Device Manager

Contents

Change Management. 2

Introduction. 2

Products Affected. 2

Procedure. 3

Sources. 3

Change Management

Introduction

In some circumstances, Windows will install drivers for a device, and that device will be removed later. When this happens, Windows still knows about the device, even though it is not shown in Device Manager. An example of this is when a USB drive is installed. Windows will install a driver for the specific device, but when it is unplugged, it is not entirely removed from Windows.

An example of when this can go wrong is in the case of an image that has been deployed on a machine with different hardware. The imaging software will most likely add in the correct drivers, but in many cases, it won’t remove the drivers from the old system. Once again, they don’t show up in Device manager, as they are not active. This can cause various problems, from event log errors, to blue screen failures.

Device manager has two types of hidden devices. There are typical hidden devices, such as non-plug and play devices, and there are ‘phantom’ devices that are not connected (“Device Manager does not display devices that are not connected to the Windows XP based computer”, 2005).

This article shows how to see these hidden devices, and how to clean them up.

Products Affected

• Microsoft Windows XP
• Microsoft Windows Server 2003
• Possibly other versions of Windows

Procedure

There are two methods of showing hidden devices in Device Manager. Firstly, typically hidden devices can be revealed by clicking View -> Show Hidden Devices

To reveal disconnected ‘phantom’ devices, follow this procedure:

1. Open a command prompt

2. Type set devmgr_show_nonpresent_devices=1

This will set a temporary environment variable which will be removed automatically later

3. Type start devmgmt.msc

Opening device manager this way is required. Opening it the regular way will not work

4. Click View -> Show Hidden Devices

Now you will be able to see ‘phantom’ devices. The icons for phantom devices will be slightly faded out. You can remove most of these devices, but be cautious on a production machine

Sources

Device Manager does not display devices that are not connected to the Windows XP based computer. (Nov 18, 2005). Retrieved March 17, 2010, from:

http://support.microsoft.com/kb/315539