Cisco Unity

Cisco Unity Event Viewer Error: "C:\WINNT\system32\dnsperf.dll" failed

Document ID: 100404

Updated: Jan 07, 2008



This document explains how to get rid of the Cisco Unity Event viewer error: "C:\WINNT\system32\dnsperf.dll" failed, which appears in the application log of the Cisco Unity Server event viewer.

Note: This document contains information about how to modify the registry in Microsoft Windows 2000 Server. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs.



Cisco recommends that you have knowledge of these topics:

  • Microsoft Windows 2000 Registry

  • Cisco Unity Voicemail Server

Components Used

The information in this document is based on these software and hardware versions:

  • Microsoft Windows 2000 Registry

  • Cisco Unity Voicemail Server

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.


Refer to Cisco Technical Tips Conventions for more information on document conventions.


This error keeps appearing in the event viewer in the Cisco Unity Server:

Source: Perflib 
event id:1008

The Open Procedure for service "DNS" in DLL "C:\WINNT\system32\dnsperf.dll" failed. Performance data for this service will not be available. Status code returned is data DWORD 0.


This problem occurs due to the perflib errors with the DNS check. Use the solution in this section in order to solve the problem.

Perform these steps in order to get rid of these errors in the application log:

  1. In order to completely remove a performance monitor extension, first identify the service name of the product that supported the custom counters.

    In this case, the service name is DNS service.

  2. Use RegEdt32.exe to traverse to the following subkey from Start > Run.

  3. Traverse to HKEY_LOCAL_MACHINE\SYSTEM\currentControlSet\Services\DNS\Performance using RegEdt32.exe.

  4. Select the Performance subkey, then click Delete from the Edit menu.

    This action deletes the Performance subkey and all its values.

  5. Delete the application log in the event viewer and reboot the Unity Server.

Related Information

Updated: Jan 07, 2008
Document ID: 100404