uint32 RemoveVirtualSystemSnapshot(
  [in]   CIM_VirtualSystemSettingData REF SnapshotSettingData,
  [out]  CIM_ConcreteJob REF Job
);

using System;
using System.Management;

namespace HyperVSamples
{
    class RemoveVirtualSystemSnapshotClass
    {
        static ManagementObject GetLastVirtualSystemSnapshot(ManagementObject vm)
        {
            ManagementObjectCollection settings = vm.GetRelated(
                "Msvm_VirtualSystemsettingData",
                "Msvm_PreviousSettingData",
                null,
                null,
                "SettingData",
                "ManagedElement",
                false,
                null);

            ManagementObject virtualSystemsetting = null;
            foreach (ManagementObject setting in settings)
            {
                Console.WriteLine(setting.Path.Path);
                Console.WriteLine(setting["ElementName"]);
                virtualSystemsetting = setting;

            }

            return virtualSystemsetting;
        }

        static void RemoveVirtualSystemSnapshot(string vmName)
        {
            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject virtualSystemService = Utility.GetServiceObject(scope, "Msvm_VirtualSystemManagementService");

            ManagementBaseObject inParams = virtualSystemService.GetMethodParameters("RemoveVirtualSystemSnapshot");

            ManagementObject vm = Utility.GetTargetComputer(vmName, scope);

            ManagementObject vmSnapshot = GetLastVirtualSystemSnapshot(vm);

            inParams["SnapshotSettingData"] = vmSnapshot.Path.Path;

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

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

                }
                else
                {
                    Console.WriteLine("Failed to remove snapshot VM");
                }
            }
            else if ((UInt32)outParams["ReturnValue"] == ReturnCode.Completed)
            {
                Console.WriteLine(outParams["SnapshotsettingData"].ToString());
                Console.WriteLine("Snapshot was removed successfully.");
            }
            else
            {
                Console.WriteLine("Remove virtual system snapshot failed with error {0}", outParams["ReturnValue"]);
            }

            inParams.Dispose();
            outParams.Dispose();
            vmSnapshot.Dispose();
            vm.Dispose();
            virtualSystemService.Dispose();
        }

        static void Main(string[] args)
        {
            if (args != null && args.Length != 1)
            {
                Console.WriteLine("Usage: RemoveVirtualSystemSnapshot vmName");
                return;
            }
            RemoveVirtualSystemSnapshot(args[0]);
        }
    }
}

option explicit 

dim objWMIService
dim managementService
dim fileSystem

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


Main()

'-----------------------------------------------------------------
' Main
'-----------------------------------------------------------------
Sub Main()
    dim computer, objArgs, vmName, vm, snapshotSetting
    
    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 = 1 then
        vmName = objArgs.Unnamed.Item(0)
    else
        WScript.Echo "usage: cscript RemoveVirtualSystemSnapshot.vbs vmName"
        WScript.Quit(1)
    end if
 
    set vm = GetComputerSystem(vmName)
    set snapshotSetting = GetComputerSystemSnapshotSettings(vm)

    if RemoveVirtualSystemSnapshot(snapshotSetting) then
        WriteLog "Done"
        WScript.Quit(0)
    else
        WriteLog "RemoveVirtualSystemSnapshot Failed."
        WScript.Quit(1)
    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)
        WScript.Quit(1)
    end if
End Function

'-----------------------------------------------------------------
' Retrieve the latest Msvm_VirtualComputerSystem snapshot
'-----------------------------------------------------------------
Function GetComputerSystemSnapshotSettings(computerSystem)
    On Error Resume Next
    dim query
    query = Format1("ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_VirtualSystemsettingData AssocClass = Msvm_PreviousSettingData", computerSystem.Path_.Path)
    set GetComputerSystemSnapshotSettings = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
        WScript.Quit(1)
    end if
End Function

'-----------------------------------------------------------------
' Revmove a virtual system Snapshot
'-----------------------------------------------------------------
Function RemoveVirtualSystemSnapshot(snapshotSettingData)

    dim objInParam, objOutParams
    
    RemoveVirtualSystemSnapshot = false
    set objInParam = managementService.Methods_("RemoveVirtualSystemSnapshot").InParameters.SpawnInstance_()
    objInParam.SnapshotSettingData = snapshotSettingData.Path_.Path
    
    set objOutParams = managementService.ExecMethod_("RemoveVirtualSystemSnapshot", objInParam)

    if objOutParams.ReturnValue = wmiStarted then
        if (WMIJobCompleted(objOutParams)) then
            RemoveVirtualSystemSnapshot = true
        end if
    elseif objOutParams.ReturnValue = wmiSuccessful then
        RemoveVirtualSystemSnapshot = true
    else
        WriteLog Format1("RemoveVirtualSystemSnapshot failed with ReturnValue {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)
        WScript.Sleep(1000)
        set WMIJob = objWMIService.Get(outParam.Job)
        jobState = WMIJob.JobState
    wend

    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(".\RemoveVirtualSystemSnapshot.log", 8, true)
    WScript.Echo line
    fileStream.WriteLine line
    fileStream.Close
End Sub


'------------------------------------------------------------------------------
' The string formating functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format2(myString, arg0, arg1)
    Format2 = Format1(myString, arg0)
    Format2 = Replace(Format2, "{1}", arg1)
End Function

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