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What are the "WMI Compatibility Options"?



There are "WMI Compatibility Options" in PRTG's settings for Probes, Groups and Devices. What do they do?

compatibility-options prtg troubleshooting tweaks wmi

Created on Mar 10, 2010 3:29:00 PM by  Volker Uffelmann [Paessler Support]

Last change on Mar 11, 2010 10:09:43 AM by  Daniel Zobel [Product Manager]

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Accepted Answer



Important notice: In PRTG version 12.4.4, we replaced "WMI Compatibility Options" with Windows Compatibility Options to take hybrid Windows sensors into consideration. See the PRTG Manual for details.

WMI Compatibility Options

PRTG offers these settings that might help you cope with various problems coming along with monitoring via WMI.

Note: This setting is deprecated. Please use the setting Windows Compatibility Options in current versions if you encounter problems while monitoring via Windows sensors.

Compatibility Settings on Probe/Group/Device Level

WMI Timeout

Important notice: In current PRTG versions, you can define a timeout in section Timeout Method under Windows Compatibility Options. The following information is partly outdated.

WMI timeout is used in certain sensors to prevent the blocking of the probe’s WMI system due to time consuming WMI queries by returning after the specified time. Its default setting (leave empty) is to use 1.5x the scanning interval of the specific sensor. If you set a specific value it will be used as time span in seconds.

You can set it in devices, groups, and probes using PRTG’s common inheritance mechanism. In sensor context you might want to set it to shorter values, so more WMI sensors can be processed.

In “Add sensor” scan context you might want to set it temporarily to longer values if PRTG can’t finish its scan.

WMI timeout applies to the following WMI sensors:

  • Disk Free
  • Event Log
  • CPU Load
  • Process
  • Network Card
  • Vital System Data

And to the following “Add sensor” WMI scans:

  • Event Log Scan
  • Network Card Scan
  • Service Scan
  • Volume Scan
  • Hyper V Scan

RPC server port

Important note: This setting is deprecated as of PRTG 9. It only applies to version PRTG 8 and older. On newer versions of PRTG this setting is removed.

WMI uses DCOM for communication between computers. Therefore the RPC Server on the monitored machine has to be accessible, by default on Port 135. This port number, however, can be altered, which would result in this error Port Error 135: RPC Server Not Accessible.

So, if the host's RPC server port has been changed, you can enter the new value using this setting.

Compatibility Settings on Sensor Level

Alternative Query

PRTG's Windows sensors are equipped with the most efficient and accurate WMI queries. However, Microsoft has changed (and will continue to do that in the future) some WMI classes over the various Windows/ServicePack/patchlevel versions, resulting in errors like "class not valid" or "invalid data".

So please try the alternative query (if available) when you keep getting errors.

This setting is visible on sensor level only and applies to the following Windows sensor types:

  • Windows CPU Load
  • WMI Memory

More information about WMI and PRTG

General introduction to WMI and PRTG

Created on Mar 10, 2010 3:35:37 PM by  Volker Uffelmann [Paessler Support]

Last change on Apr 8, 2022 9:29:31 AM by  Frank Hadasch [Paessler Support] (0) 1

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.