Getting a List of Installed Applications on Local and Remote Computers

Introduction

A few months ago, I was asked to have a look at a PowerShell script which was supposed to be able to list installed applications on the local and remote Windows computers on the network.

The script was from the Microsoft Gallery site.

Here is the original script, with explanations of what it's supposed to do.

https://gallery.technet.microsoft.com/scriptcenter/Get-a-List-of-Installed-c47393ed/view/Discussions

Unfortunately if you run the script, it will only list the applications installed on the local PC but outputs the same results for all the computers that you are trying to inventory.

I found that the program was very well structured so perhaps the author did this on purpose. Anyhow, I modified the Function FindInstalledApplicationInfo($ComputerName)
and used .NET's remote registry functions in place of the original PowerShell registry functions which looks at the local registry only. In this way, the .NET's remote registry functions can look at the local registry or remote Windows computers registry.

Feel free to use the whole script or if you have come to this page trying to resolve the original script's issues, just look at the FindInstalledApplicationInfo function.

Full Listing of the Get List of Installed Applications script

#--------------------------------------------------------------------------------- 
#The sample scripts are not supported under any Microsoft standard support 
#program or service. The sample scripts are provided AS IS without warranty  
#of any kind. Microsoft further disclaims all implied warranties including,  
#without limitation, any implied warranties of merchantability or of fitness for 
#a particular purpose. The entire risk arising out of the use or performance of  
#the sample scripts and documentation remains with you. In no event shall 
#Microsoft, its authors, or anyone else involved in the creation, production, or 
#delivery of the scripts be liable for any damages whatsoever (including, 
#without limitation, damages for loss of business profits, business interruption, 
#loss of business information, or other pecuniary loss) arising out of the use 
#of or inability to use the sample scripts or documentation, even if Microsoft 
#has been advised of the possibility of such damages 
#--------------------------------------------------------------------------------- 

#requires -version 3

# SoftwareAudit-Lib version 1.0 Date: 13/06/2017
#
# The system that this script runs on needs to have PowerShell 3.0 or above.
# You will also require admin rights to the PCs that are being scanned.
# 
#
# This script needs to be imported before it can be used.
# The syntax to import this script module in a PowerShell environment is:
#
# import-module "DRIVE:\Full Path\..\..\SoftwareAudit-Lib.psm1"
#
# If you are going to be running another script to make use of this script module, it is best to import this script as part of the calling script.
# This ensures the below function is available to the calling program.
#
# NOTE: If you have to make changes to any functions below, remember to exit out of a PowerShell session
# and re-import this script for the changes to take effect


Function Get-OSCInstalledApplication
{
<#
  .SYNOPSIS
        Get-OSCInstalledApplication is an advanced function which can be used to get installed application on local or remote computer.
    .DESCRIPTION
        Get-OSCInstalledApplication is an advanced function which can be used to get installed application on local or remote computer.
    .PARAMETER  ComputerName
  Gets the installed application on the specified computers. 
    .PARAMETER  ComputerFilePath
  Specifies the path to the CSV file. This file should contain one or more computers. 
    .EXAMPLE
        C:\PS> Get-OSCInstalledApplication -ComputerName "Server201201","Server201202"
  
  This command will list installed application on 'Server201201' and 'Server201202'.
    .EXAMPLE
        C:\PS> Get-OSCInstalledApplication -ComputerFilePath C:\Script\ComputerList.csv
  
  This command specifies the path to an item that contains several computers. Then 'Get-OSCInstalledApplication' cmdlet will list installed application from thoese computers.
    .EXAMPLE
        C:\PS> Get-OSCInstalledApplication -ComputerName "Server201201" | Export-Csv -Path C:\installedApps.csv
  
  This command will list installed application on 'Server201201' and saves the strings in a CSV file.
#>
    [CmdletBinding(DefaultParameterSetName='SinglePoint')]
    Param
    (
        [Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true, ValueFromPipelineByPropertyName=$true, ParameterSetName="SinglePoint")]
        [Alias('CName')][String[]]$ComputerName,
        [Parameter(Mandatory=$true, Position=0, ParameterSetName="MultiplePoint")]
        [Alias('CNPath')][String]$ComputerFilePath
    )
    
    If($ComputerName)
    {
        Foreach($CN in $ComputerName)
        {
            #Test computer connectivity
            $PingResult = Test-Connection -ComputerName $CN -Count 1 -Quiet
            If($PingResult) 

            {

# If PC is on the network, start remoteregistry service on PC, then start scanning for installed apps

       Set-Service –Name remoteregistry –Computer $CN -StartupType Automatic
       Get-Service remoteregistry -ComputerName $CN | start-service
       Start-Sleep -s 5
       write-host "Trying to find applications on " $CN
       FindInstalledApplicationInfo -ComputerName $CN
            }
            Else
            { 

# If PC is not on the network, return the PC name with one application Display Name as "Computer Offline"
       $Objs = @()
       Write-Warning "Failed to connect to computer '$CN'."
       $Obj = [PSCustomObject]@{Computer=$CN;
                                 DisplayName = "Computer Offline";
                                 DisplayVersion = "";
                                 Publisher = "";
       ApplicationType = "" }
       $Objs += $Obj
       $Objs | Where-Object { $_.DisplayName } 
            }
        }
    }

    If($ComputerFilePath)
    {
        $ComputerName = (Import-Csv -Path $ComputerFilePath).ComputerName

        Foreach($CN in $ComputerName)
        {
            FindInstalledApplicationInfo -ComputerName $CN
        }
    }
}

# This next function checks the Software Uninstall registry of the PC and lists the values, which represents

# the installed applications

Function FindInstalledApplicationInfo($ComputerName)
{

$Objs = @()

$key = "Software\Microsoft\Windows\CurrentVersion\Uninstall"
$key_32bit = "SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall"

$type = [Microsoft.Win32.RegistryHive]::LocalMachine

$regKey = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($type, $ComputerName)
$subRegKey=[Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($type, $ComputerName)

$regKey_32bit = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($type, $ComputerName)
$subRegKey_32bit = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey($type, $ComputerName)


#Check if it is a 64 bit PC by checking the existence of the Software Wow64Node. It is 64 bit if the

#Wow64Node exists.

$is64Bit=$regKey_32bit.OpenSubkey($key_32bit)

if ($is64Bit -eq $null) { $applicationBitType="32 Bit"
} else {
  $applicationBitType="64 Bit"
}

# Getting the list of installed applications from the SOFTWARE Uninstall Registry Key
# They are 64 bit if the Wow64Node exists, otherwise the applications are 32 bit.

$regKey = $regKey.OpenSubKey($key)
$sub=$regKey.GetSubKeyNames()


Foreach($sub1 in $sub){
  $subKey=$key + "\" + $sub1.toString()

  $InstalledApp=$subRegKey.OpenSubKey($subKey)

    
     
    $Obj = [PSCustomObject]@{Computer=$ComputerName;
                                 DisplayName = $InstalledApp.GetValue("DisplayName");
                                 DisplayVersion = $InstalledApp.GetValue("DisplayVersion");
                                 Publisher = $InstalledApp.GetValue("Publisher");
            ApplicationType = $applicationBitType }
     
 
 $Objs += $Obj
  
}


# Getting the list of installed 32 bit Applications for a 64 bit PC

if ($is64Bit -ne $null) {
$regKey_32bit = $regKey_32bit.OpenSubkey($key_32bit)
$sub_32bit=$regKey_32bit.GetSubKeyNames()


 Foreach($sub1_32bit in $sub_32bit){
  $subKey_32bit=$key_32bit + "\" + $sub1_32bit.toString()
  
  $InstalledApps_32bit=$subRegKey_32bit.OpenSubKey($subKey_32bit)
  
 
    
 $Obj = [PSCustomObject]@{Computer=$ComputerName;
                                 DisplayName = $InstalledApps_32bit.GetValue("DisplayName");
                                 DisplayVersion = $InstalledApps_32bit.GetValue("DisplayVersion");
                                 Publisher = $InstalledApps_32bit.GetValue("Publisher");
            ApplicationType = "32 Bit" }
      
  
  
  $Objs += $Obj
 }
}

$Objs | Where-Object { $_.DisplayName } 


}