Getting software version using registry keys in PowerShell

Question

I have a script that gets the installed software version from all of the servers by using the registry keys but I am encountering the following errors. Sorry Im new to PowerShell. Appreciate the help.

   Cannot find an overload for "OpenRemoteBaseKey" and the argument count: "1".
   At C:\Users\P1334126\Scripts\GetInstalledSoftware.ps1:12 char:5 
+     $reg = [microsoft.win32.registrykey]::OpenRemoteBaseKey('LocalMac ...
+  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], MethodException
    + FullyQualifiedErrorId : MethodCountCouldNotFindBest


You cannot call a method on a null-valued expression.
At C:\Users\P1334126\Scripts\GetInstalledSoftware.ps1:16 char:5
 +     $regkey = $reg.OpenSubKey($UninstallKey)
 +   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

You cannot call a method on a null-valued expression.
At C:\Users\P1334126\Scripts\GetInstalledSoftware.ps1:20 char:5
+     $subkeys = $regkey.GetSubKeyNames()
+   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

My script is the following

## Include CSV file of all computers with header "pc"
$computers = Import-Csv "C:\Users\P1334126\Documents\Test.CSV"

$array = @()  
#Define the variable to hold the location of Currently Installed Programs
foreach($pc in $computers){
$computername=$pc.computername
$UninstallKey = "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall"

#Create an instance of the Registry Object and open the HKLM base key

$reg = [microsoft.win32.registrykey]::OpenRemoteBaseKey('LocalMachine')

#Drill down into the Uninstall key using the OpenSubKey Method

$regkey = $reg.OpenSubKey($UninstallKey) 

#Retrieve an array of string that contain all the subkey names

$subkeys = $regkey.GetSubKeyNames() 

#Open each Subkey and use GetValue Method to return the required values for each

foreach($key in $subkeys){

  $thisKey=$UninstallKey + '\\' + $key 

  $thisSubKey=$reg.OpenSubKey($thisKey) 

  $obj = New-Object PSObject
  
  $obj | Add-Member -MemberType NoteProperty -Name 'ComputerName' -Value $computername

  $obj | Add-Member -MemberType NoteProperty -Name 'DisplayName' -Value $($thisSubKey.GetValue("DisplayName"))

  $obj | Add-Member -MemberType NoteProperty -Name 'DisplayVersion' -Value $($thisSubKey.GetValue("DisplayVersion"))
  
  $obj | Add-Member -MemberType NoteProperty -Name 'Publisher' -Value $($thisSubKey.GetValue("Publisher"))

  $array += $obj
  }

}

$array | Select-Object ComputerName, DisplayName, DisplayVersion, Publisher | Sort-Object -Property ComputerName | Out-File InstalledSoftware.txt

Doug Maurer Doug Maurer · Accepted Answer · 2020-12-08T04:36:06

OpenRemoteBaseKey has 2 overloads, neither takes a single argument.

OverloadDefinitions                                                                                                                                                                           
-------------------                                                                                                                                                                           
static Microsoft.Win32.RegistryKey OpenRemoteBaseKey(Microsoft.Win32.RegistryHive hKey, 
string machineName)                                                                                   
static Microsoft.Win32.RegistryKey OpenRemoteBaseKey(Microsoft.Win32.RegistryHive hKey, 
string machineName, Microsoft.Win32.RegistryView view)

Example

$reg = [microsoft.win32.registrykey]::OpenRemoteBaseKey('LocalMachine',SomeComputerName)

If you're not querying a remote machine, then use OpenBaseKey

Getting software version using registry keys in PowerShell

1 Answers