<%NUMBERING1%>.<%NUMBERING2%>.<%NUMBERING3%> PRTG Manual: WMI Volume Sensor

The WMI Volume sensor monitors the free disk space on a drive, logical volume, or mount point via Windows Management Instrumentation (WMI).

i_round_redThe sensor does not support disk drive management.

i_round_blueThe sensor monitors an area of storage on a hard disk. It can monitor local volumes that are formatted, unformatted, mounted, or offline. A volume is formatted by using a file system such as file allocation table (FAT) or New Technology File System (NTFS), and might have a drive letter assigned to it. One hard disk can have multiple volumes, and volumes can span multiple physical disks.

WMI Volume Sensor

WMI Volume Sensor

i_square_cyanFor a detailed list and descriptions of the channels that this sensor can show, see section Channel List.

Sensor in Other Languages

  • Dutch: WMI Volume
  • French: Espace disponible du disque (WMI)
  • German: WMI Datenträger
  • Japanese: WMI ボリューム
  • Portuguese: Volume (WMI)
  • Russian: Том WMI
  • Simplified Chinese: WMI 卷
  • Spanish: Volumen (WMI)


Consider the following remarks and requirements for this sensor:



Performance impact

  • This sensor has a high performance impact. Stay below 200 WMI sensors per probe. Above this number, consider using multiple remote probes for load balancing.


  • This sensor requires WoW64 (Windows 32-bit on Windows 64-bit) for target systems that run Windows Server 2016.


  • This sensor requires credentials for Windows systems.

Windows version

  • This sensor does not support Windows XP and earlier.


  • This sensor supports IPv6.


  • This sensor has predefined limits for several metrics.

Hosted probe

i_podYou cannot add this sensor to the hosted probe of a PRTG Hosted Monitor instance. If you want to use this sensor, add it to a remote probe device.

Basic Sensor Settings

Basic Sensor Settings

Basic Sensor Settings

The sensor has the following default tags that are automatically predefined in the sensor's settings when you add the sensor:

  • diskspacesensor
  • wmivolumesensor

i_square_cyanFor more information about basic sensor settings, see section Sensor Settings.

WMI Volume Specific

WMI Volume Specific

WMI Volume Specific




The unique identifier of the volume (drive, logical volume, mount point) that this sensor monitors.

Drive Type

The type of disk drive that this sensor monitors.

ID Selection

Define how the sensor identifies the volume:

  • Use system device ID (default): Use the system device ID. This is usually the best option for this sensor because the device ID does not change when the volume is renamed.
  • Use drive letter: Use the drive letter. In a Microsoft cluster environment, the device ID changes when the cluster is switched to a different node. We recommend that you select this option in this case.

Drive Letter

This setting is only visible if you select Use drive letter above.

Enter the letter of the drive that you want to monitor followed by a colon, for example, C:

Debug Options

Debug Options

Debug Options



Result Handling

Define what PRTG does with the sensor result:

  • Discard result (default): Do not store the sensor result.
  • Store result: Store the last sensor result in the \Logs\sensors subfolder of the PRTG data directory on the probe system. The file name is Result of Sensor [ID].Data.txt. This setting is for debugging purposes. PRTG overwrites this file with each scanning interval.

i_round_blueIn a cluster, PRTG stores the result in the PRTG data directory of the master node.

Sensor Display

Sensor Display

Sensor Display



Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, PRTG displays the last value of the primary channel below the sensor's name. The available options depend on what channels are available for this sensor.

i_round_blueYou can set a different primary channel later by clicking b_channel_primary below a channel gauge on the sensor's Overview tab.

Graph Type

Define how this sensor shows different channels:

  • Show channels independently (default): Show a graph for each channel.
  • Stack channels on top of each other: Stack channels on top of each other to create a multi-channel graph. This generates a graph that visualizes the different components of your total traffic.
    i_round_redYou cannot use this option in combination with manual Vertical Axis Scaling (available in the channel settings).

Stack Unit

This setting is only visible if you select Stack channels on top of each other above.

Select a unit from the list. PRTG stacks all channels with this unit on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all of these settings are inherited from objects that are higher in the hierarchy. We recommend that you change them centrally in the root group settings if necessary. To change a setting for this object only, click b_inherited_enabled under the corresponding setting name to disable the inheritance and to display its options.

i_square_cyanFor more information, see section Inheritance of Settings.

Channel List

i_round_blueWhich channels the sensor actually shows might depend on the target device, the available components, and the sensor setup.




In the channel table on the Overview tab, this channel never shows any values. PRTG uses this channel in graphs and reports to show the amount of time in which the sensor was in the Down status

Free Bytes

The free space

Free Space

The free space (%)

i_round_blueThis channel is the primary channel by default.

i_round_blueThis channel has default limits:

  • Lower error limit: 10%
  • Lower warning limit: 25%


i_square_blueKNOWLEDGE BASE

What security features does PRTG include?

My WMI sensors don't work. What can I do?