Unable to download the windows update using script - vbscript

Question

I am running Windows 2015 LTSB and use below script to download the Windows patches as and when required.
Previously the below script use to work from normal user, but from past few days it just shows the message as
Download completed successfully. Please press any key to continue.
Where actually nothing is downloaded and this script doesn't go to install updates.
And when I execute the same script from user with Admin privileges, it downloads and installs the relevant update packages.
I suspect that downloader.Download() is behaving differently for Admin and Normal user.
Can you please assist me in knowing what is the cause of updates not getting downloaded from normal user.
Option Explicit
Dim updateSession, updateSearcher, update, searchResult, downloader, updatesToDownload, updatesToInstall, installer, installationResult, InputKey, i, endKey
If Right((LCase(WScript.FullName)),11) <> "cscript.exe" Then
WScript.Echo "Please carry out this script using CSCRIPT.EXE." & _
vbCrLf & "Example: cscript WindowsUpdate.vbs"
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
endKey = WScript.StdIn.ReadLine
WScript.Quit(0)
End If
Dim strInp
On Error Resume Next
WScript.Echo "Press Enter key to begin Windows Update."
strInp = WScript.StdIn.ReadLine
WScript.Echo "------------------------------"
WScript.Echo "Windows Update"
WScript.Echo "------------------------------"
WScript.Echo "Verifying latest update..."
Set updateSession = CreateObject("Microsoft.Update.Session")
Set updateSearcher = updateSession.CreateupdateSearcher()
Set searchResult = _
updateSearcher.Search("IsInstalled=0 and Type='Software' and AutoSelectOnWebSites=1")
'If Err.Number <> 0 Then
If IsNull(searchResult.Updates.Count) Or IsEmpty(searchResult.Updates.Count) Then
WScript.Echo "An error occurred. Please check your network connection and try again."
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
endKey = WScript.StdIn.ReadLine
'Err.Clear
WScript.Quit(0)
End If
For i = 0 To searchResult.Updates.Count-1
Set update = searchResult.Updates.Item(i)
WScript.Echo i + 1 & vbTab & update.Title & " Size: " & update.MaxDownloadSize
Next
If searchResult.Updates.Count = 0 Then
WScript.Echo "Windows is up to date."
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
endKey = WScript.StdIn.ReadLine
WScript.Quit(0)
Else
WScript.Echo "A newer version of " & searchResult.Updates.Count & _
" is found. Downloading starts."
End If
WScript.StdOut.Write "Preparing download..."
Set updatesToDownload = CreateObject("Microsoft.Update.UpdateColl")
For i = 0 to searchResult.Updates.Count-1
Set update = searchResult.Updates.Item(i)
WScript.StdOut.Write "."
updatesToDownload.Add(update)
Next
WScript.Echo vbCrLf & "Newer version of programs is downloading..."
Set downloader = updateSession.CreateUpdateDownloader()
downloader.Updates = updatesToDownload
downloader.Download()
'WScript.Echo "DEBUG [downloader.Download().ResultCode]:" & downloader.Download().ResultCode
If downloader.Download().ResultCode = 2 Then
WScript.Echo "Download completed successfully."
Else
WScript.Echo "Download failed."
End If
If downloader.Download().ResultCode = 4 Then
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
endKey = WScript.StdIn.ReadLine
WScript.Quit(0)
End If
WScript.Echo "Download the following programs is successfully completed."
For i = 0 To searchResult.Updates.Count-1
Set update = searchResult.Updates.Item(i)
If update.IsDownloaded Then
WScript.Echo i + 1 & vbTab & update.Title
End If
Next
Set updatesToInstall = CreateObject("Microsoft.Update.UpdateColl")
WScript.StdOut.Write "Preparing installation..."
For i = 0 To searchResult.Updates.Count-1
Set update = searchResult.Updates.Item(i)
If update.IsDownloaded = True Then
WScript.StdOut.Write "."
updatesToInstall.Add(update)
End If
Next
'WScript.StdOut.Write vbCrLf & "DEBUG [updatesToInstall.Count]:" & updatesToInstall.Count
If updatesToInstall.Count = 0 Then
WScript.Echo vbCrLf & "Installation failed."
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
endKey = WScript.StdIn.ReadLine
WScript.Quit(0)
End If
WScript.Echo vbCrLf & "Installing..."
Set installer = updateSession.CreateUpdateInstaller()
installer.Updates = updatesToInstall
Set installationResult = installer.Install()
If installationResult.ResultCode = 2 Then
WScript.Echo "Installation completed successfully."
Else
WScript.Echo "Installation failed."
End If
WScript.Echo "Detail information."
For i = 0 to updatesToInstall.Count - 1
WScript.StdOut.Write i + 1 & vbTab & _
updatesToInstall.Item(i).Title
If installationResult.GetUpdateResult(i).ResultCode = 2 then
WScript.Echo "Succeed."
Else
WScript.Echo "Failure."
End If
Next
'WScript.StdOut.Write "Restart is required."
If installationResult.RebootRequired Then
'WScript.Echo "Required."
WScript.Echo "Computer restart is required to complete installation."
Else
WScript.Echo "Computer restart is not required."
End If
WScript.StdOut.Write vbCrLf & "Please press any key to continue."
InputKey = WScript.StdIn.ReadLine
If installationResult.RebootRequired Then
Dim objWshShell
Set objWshShell = WScript.CreateObject("WScript.Shell")
objWshShell.Run "%comspec% /c shutdown /r /t 0", 0, False
WScript.Quit(-1)
Else
WScript.Quit(0)
End If