AllUsers-Registrykeys.ps1

# An example template powershell script that will allow you to work with the user registry keys for all users 
# on a system or terminal server. It will check if the ntuser.dat file is mounted, and if not mount it with the 
# users SID. If the ntuser.dat file was one mounted by the script (ie, user is not logged in), it will unmount 
# the dat file after.

# This script uses the example of querying and displaying the set default printer per user for all users on a
# system.

$users = Get-WMIObject Win32_UserAccount
$hku = New-PSDrive -PSProvider Registry -Name HKU -Root HKEY_USERS

$users | Foreach-Object {
	$user = $_
	$ntdat_mounted = $null
  	If (!($user.Caption -like '*Administrator')) {
		If (Test-Path ('HKLM:\Software\Microsoft\Windows NT\CurrentVersion\ProfileList\' + $user.SID) -ErrorAction SilentlyContinue) {
			$profileImagePath = (Get-ItemProperty -Path ('HKLM:\Software\Microsoft\Windows NT\CurrentVersion\ProfileList\' + $user.SID)).ProfileImagePath

			# Check if Registry Keys already Loaded. Load if not loaded.
			If (!(Test-Path ('HKU:\' + $user.SID) -ErrorAction SilentlyContinue)) {
				If (Test-Path ($profileImagePath + '\ntuser.dat') -ErrorAction SilentlyContinue) {
					$ntdat_mounted = $true
					reg load ('HKU\' + $user.SID) ($profileImagePath + '\ntuser.dat') | Out-Null
				}
			}

      			If (Test-Path ('HKU:\' + $user.SID) -ErrorAction SilentlyContinue) {
        			$defaultPrinter = (Get-ItemProperty -Path ('HKU:\' + $user.SID + '\Software\Microsoft\Windows NT\CurrentVersion\Windows\')).Device
        			Write-Host ("User:[" + $user.FullName + "] DefaultPrinter:[" + $defaultPrinter + "]")
      			}

			# Unload Registry Key if Loaded
			If ($ntdat_mounted) { 
        			reg unload ('HKU\' + $user.SID) | Out-Null
			}
    		}
	}
}