PS/2 Keyboard/Mouse Not Recognized When Plugged Into Running Computer


If a PS/2-style keyboard and/or Mouse is not connected to the computer before Windows 2000 startup, the keyboard is not recognized if you connect it later.


To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The English version of this fix should have the following file attributes or later:

Date Time Version Size File name
02/04/2002 10:19 AM 5.0.2195.4900 48,720 i8042prt.sys

When you install this hotfix by using the hotfix package, the following registry items are created and set to add "hotplugging" capability:

Key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\Parameters
Value: Headless
Data: 0x1 (Allow hotplugging a PS/2-style keyboard. To disable this feature, set the data value to 0.)
This hotfix was updated on 2/4/2002. The updated hotfix also prevents the following error messages from appearing in the event log when you detach a USB keyboard:

  • Type: Warning
    Source: i8042prt
    Event: 32
    Description: The keyboard device does not exist or was not detected.
    Type: Error
    Source: i8042prt
    Event: 26
    Description: Exceeded the allowable number of retries (configurable via the registry) on device.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows

If you need to log the error messages, change the value of the ReportResetErrors value in the following registry key to 1:

NOTE: This feature is highly dependent on the computer's BIOS. Because PS/2 hotplug is not in the PS/2 specification, some PS/2 controllers may not correctly handle "hotplugging" of a device, and some may short out devices. This new driver does nothing special to accommodate hotplug other than ignore initialization errors.

NOTE: This hotfix also corrects a problem that causes the operating system to stop responding on a Dell PE2550, which uses a USB keyboard.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 3.

More Information

For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base:

265173 The Datacenter Program and Windows 2000 Datacenter Server Product
For additional information about how to install multiple hotfixes with only one reboot, click the article number below to view the article in the Microsoft Knowledge Base:

296861 Use QChain.exe to Install Multiple Hotfixes with One Reboot

Artikelnummer: 262798 – Letzte Überarbeitung: 19.06.2014 – Revision: 1