Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib

Data type Range Default value


0x0–0xEE6B2800 milliseconds

0x2710 (10 seconds)


Defines a slow Open procedure call for the performance counter dynamic-link libraries (DLLs) on the system.

When an Open procedure call takes longer to complete than the time specified in the value of this entry, then by default, Perflib records an error in the Application Log. However, if the value of Configuration Flags is 0x0, then Perflib disables the counter DLL and does not load the counters again until you have manually reenabled them.

Perflib times the procedure calls of non-trusted counters to identify counters that can delay or lock performance tools during initialization. While the Open procedure call proceeds, you cannot use the performance tools, and remote users cannot log on to the local computer.

This entry does not exist in the registry by default. You can add it by using the registry editor Regedit.exe.

Activation Method

To make changes to this entry effective, restart Windows.


  • Perflib disables counters by setting the value of Disable Performance Counters for that service to 1. After you have repaired or replaced the counters, you must re-enable them manually by changing the value of Disable Performance Counters to 1.

  • Perflib does not time the procedure calls of trusted performance counter DLLs This entry applies only to non-trusted DLLs.

  • This entry applies to all counter DLLs on this system. To adjust the Open procedure time for the counters of a particular service, use the Open Timeout entry.

  • The value of this entry is also the default value of the Collect Timeout entry.

  • This entry has a different effect on Windows 2000 and Windows Server 2003 than it has on Windows NT 4.0 and earlier. In Windows NT 4.0 and earlier, it determines the Open procedure wait time only for extensible counters. For more information, see Regentry.hlp in the Windows NT Resource Kit 4.0.


  • If you suspect problems with procedure calls, check the Application Log in Event Viewer. Perflib records an error in the log whenever a procedure call exceeds its limit.

See Also


Open Timeout
Configuration Flags
Collect Timeout