PowerShell logon script to log Microsoft Office version - powershell

Question

I came across PowerShell script to log Microsoft Office version of remote computer on domain. I want to run it as logon script to I modified OpenRemoteBaseKey to OpenBaseKey and this is the code:
$version = 0
$reg = [Microsoft.Win32.RegistryKey]::OpenBaseKey('LocalMachine', 'Default')
$reg.OpenSubKey('software\Microsoft\Office').GetSubKeyNames() |% {
if ($_ -match '(\d+)\.') {
if ([int]$matches[1] -gt $version) {
$version = $matches[1]
}
}
}
if ($version) {
Add-Content -Path \\server\share\oversion.txt -Value "$env:computername $env:username : $version"
}
else {
Add-Content -Path \\server\share\oversion.txt -Value "$env:computername $env:username : 0"
}
but now I receive error:
You cannot call a method on a null-valued expression.
At line:4 char:1
+ $reg.OpenSubKey('software\Microsoft\Office').GetSubKeyNames() |% {
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull
but not sure what this means since GetSubKeyNames seems valid: https://learn.microsoft.com/en-us/dotnet/api/microsoft.win32.registrykey.getsubkeynames?view=netframework-4.7.2, also it works with OpenRemoteBaseKey, can someone point me to right direction, please?

Answer 1

I'm not sure why OpenRemoteBaseKey works, but OpenBaseKey doesn't because I cannot reproduce that..
You might however try the more Powershell way of doing this:
$version = 0
Get-ChildItem -Path 'HKLM:\SOFTWARE\Microsoft\Office' -Name | Where-Object {$_ -match '(\d+)\.\d+'} | ForEach-Object {
$version = [math]::Max([int]$_, $version)
}
Add-Content -Path \\server\share\oversion.txt -Value "$env:COMPUTERNAME $env:USERNAME : $version"