Testing for the Presence of a Registry Key and Value

There are a number of different ways to test for the presence of a registry key and value in PowerShell. Here’s how I like to go about it. We’ll use an example key HKLM:\SOFTWARE\TestSoftware with a single value Version:

Check for the key

You can use the Test-Path cmdlet to check for the key, but not for specific values within a key. For example

Test-Path 'HKLM:\\SOFTWARE\\TestSoftware'

but not

Test-Path 'HKLM:\\SOFTWARE\\TestSoftware\\Version'

So for the value we need to work a bit harder. Using the below function we can see if Get-ItemProperty contains the value or not.

function Test-RegistryValue {

param (

\[parameter(Mandatory=$true)\] \[ValidateNotNullOrEmpty()\]$Path,

\[parameter(Mandatory=$true)\] \[ValidateNotNullOrEmpty()\]$Value )

try {

Get-ItemProperty -Path $Path | Select-Object -ExpandProperty $Value -ErrorAction Stop | Out-Null return $true }

catch {

return $false

}

}

So for our example:

Test-RegistryValue -Path 'HKLM:\\SOFTWARE\\TestSoftware' -Value 'Version' Test-RegistryValue -Path 'HKLM:\\SOFTWARE\\TestSoftware' -Value 'Banana'