RemoveKvpItems method of the Msvm_VirtualSystemManagementService class

Removes existing key-value pairs from a virtual system.


uint32 RemoveKvpItems(
  [in]  CIM_ComputerSystem REF TargetSystem,
  [in]  string                 DataItems[],
  [out] CIM_ConcreteJob    REF Job


TargetSystem [in]

Type: CIM_ComputerSystem

A reference to the virtual system on which the key-value pairs will be removed.

DataItems [in]

Type: string[]

An array of key-value pairs to be removed (only the keys need to match). Each element of the array is an embedded instance of the Msvm_KvpExchangeDataItem class. This method fails if any of the specified key-value pairs does not exist on the target system. This array can contain at most 128 elements.

Job [out]

Type: CIM_ConcreteJob

An optional parameter for monitoring progress of the operation, which is used if the method could not be executed synchronously. If the operation is executing asynchronously, the return value is 4096.

Return value

Type: uint32

This method returns one of the following values.

Completed with No Error (0)

Method Parameters Checked - Job Started (4096)

Failed (32768)

Access Denied (32769)

Not Supported (32770)

Status is unknown (32771)

Timeout (32772)

Invalid parameter (32773)

System is in use (32774)

Invalid state for this operation (32775)

Incorrect data type (32776)

System is not available (32777)

Out of memory (32778)


Access to the Msvm_VirtualSystemManagementService class might be restricted by UAC Filtering. For more information, see User Account Control and WMI.


The following C# sample removes key-value pairs from a virtual system. The referenced utilities can be found in Common Utilities for the Virtualization Samples.

To function correctly, the following code must be run on the VM host server, and must be run with Administrator privileges.

using System;
using System.Management;

namespace HyperVSamples
    class RemoveKvpItemsClass
        static void RemoveKvpItems(string vmName, string itemName)
            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject virtualSystemService = Utility.GetServiceObject(scope, "Msvm_VirtualSystemManagementService");
            ManagementBaseObject inParams = virtualSystemService.GetMethodParameters("RemoveKvpItems");
            ManagementClass kvpExchangeDataItem = new ManagementClass(scope, new ManagementPath("Msvm_KvpExchangeDataItem"), null);

            ManagementObject dataItem = kvpExchangeDataItem.CreateInstance();

            dataItem["Data"] = "";
            dataItem["Name"] = itemName;
            dataItem["Source"] = 0;

            string[] dataItems = new string[1];
            dataItems[0] = dataItem.GetText(TextFormat.CimDtd20);

            ManagementObject vm = Utility.GetTargetComputer(vmName, scope);
            inParams["TargetSystem"] = vm.Path.Path;
            inParams["DataItems"] = dataItems;

            ManagementBaseObject outParams = virtualSystemService.InvokeMethod("RemoveKvpItems", inParams, null);

            if ((UInt32)outParams["ReturnValue"] == ReturnCode.Started)
                if (Utility.JobCompleted(outParams, scope))
                    Console.WriteLine("KvpItems were removed successfully.");

                    Console.WriteLine("Failed to remove KvpItems");
            else if ((UInt32)outParams["ReturnValue"] == ReturnCode.Completed)
                Console.WriteLine("KvpItems were removed successfully.");
                Console.WriteLine("Remove KvpItems failed with error {0}", outParams["ReturnValue"]);


        static void Main(string[] args)
            if (args != null && args.Length != 3)
                Console.WriteLine("Usage: RemoveKvpItems vmName itemName");
            RemoveKvpItems(args[0], args[1]);

The following VBScript sample removes key-value pairs from a virtual system.

To function correctly, the following code must be run on the VM host server, and must be run with Administrator privileges.

option explicit 

dim objWMIService
dim managementService
dim fileSystem

const JobStarting = 3
const JobRunning = 4
const JobCompleted = 7
const wmiStarted = 4096
const wmiSuccessful = 0


' Main
Sub Main()

    dim computer, vmName, itemName, myVm, objArgs
    set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")

    computer = "."

    set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization")
    set managementService = objWMIService.ExecQuery("select * from Msvm_VirtualSystemManagementService").ItemIndex(0)

    set objArgs = WScript.Arguments
    if WScript.Arguments.Count = 3 then
        vmName = objArgs.Unnamed.Item(0)
        itemName = objArgs.Unnamed.Item(1)
        WScript.Echo "usage: cscript AddKvpItems.vbs vmName itemName"
    end if

    set myVm = GetComputerSystem(vmName)

    if RemoveKvpItems(myVm, itemName) then

        WriteLog "Done"

        WriteLog "RemoveKvpItems failed"
    end if
End Sub

' Retrieve Msvm_VirtualComputerSystem from base on its ElementName
Function GetComputerSystem(vmElementName)
    On Error Resume Next
    dim query
    query = Format1("select * from Msvm_ComputerSystem where ElementName = '{0}'", vmElementName)
    set GetComputerSystem = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
    end if
End Function

' RemoveKvpItems
Function RemoveKvpItems(computerSystem, itemName)

    dim dataItem, dataItems, objInParam, objOutParams
    RemoveKvpItems = false
    set dataItem = objWMIService.Get("Msvm_KvpExchangeDataItem").SpawnInstance_()
    dataItem.Data = ""
    dataItem.Name = itemName
    dataItem.Source = 0
    dataItems = Array(1)
    dataItems(0) = dataItem.GetText_(1)
    set objInParam = managementService.Methods_("RemoveKvpItems").InParameters.SpawnInstance_()
    objInParam.TargetSystem = computerSystem.Path_.Path
    objInParam.dataItems = dataItems
    set objOutParams = managementService.ExecMethod_("RemoveKvpItems", objInParam)

    if objOutParams.ReturnValue = wmiStarted then
        if (WMIJobCompleted(objOutParams)) then
            RemoveKvpItems = true
        end if
    elseif objOutParams.ReturnValue = wmiSuccessful then
        RemoveKvpItems = true
        WriteLog Format1("RemoveKvpItems failed with {0}", objOutParams.ReturnValue )
    end if

End Function

' Handle wmi Job object
Function WMIJobCompleted(outParam)

    dim WMIJob, jobState
    WMIJobCompleted = true

    set WMIJob = objWMIService.Get(outParam.Job)
    jobState = WMIJob.JobState

    while jobState = JobRunning or jobState = JobStarting
        WriteLog Format1("In progress... {0}% completed.",WMIJob.PercentComplete)
        set WMIJob = objWMIService.Get(outParam.Job)
        jobState = WMIJob.JobState

    if (WMIJob.JobState <> JobCompleted) then
        WriteLog Format1("ErrorDescription:{0}", WMIJob.ErrorDescription)
        WriteLog Format1("ErrorCode:{0}", WMIJob.ErrorCode)
        WMIJobCompleted = false
    end if

End Function

' Create the console log files.
Sub WriteLog(line)
    dim fileStream
    set fileStream = fileSystem.OpenTextFile(".\RemoveKvpItems.log", 8, true)
    WScript.Echo line
    fileStream.WriteLine line

End Sub

' The string formatting functions to avoid string concatenation.
Function Format1(myString, arg0)
    Format1 = Replace(myString, "{0}", arg0)
End Function


Minimum supported client
None supported
Minimum supported server
Windows Server 2008
End of client support
None supported
End of server support
Windows Server 2012

See also