Repair-RegistryPol.ps1

<#
.Synopsis
   Clean up machines with bad (old/corrupt) machine Registry.pol files
.DESCRIPTION
   Taking a array as input, this cmdlet assists in keeping machines in a healthy state to accept Group Policy driven changes
   by confirming the last modified date of the machines Registry.pol and if older than a day , remove it, (or doesn't exist)
   followed by a forced Machine Policy update.
   To work against older WMF/Powershell environments, invoke-command + invoke-gpupdate have been avoided.
.EXAMPLE
   Repair-RegistryPol -Computers workstation1,workstation2
.EXAMPLE
   Repair-RegistryPol -Computers (Import-Csv lotsofworkstations.csv)
.NOTES
   Version:        1.0
   Author:         James Pettigrove
#>

[CmdletBinding()]
Param (
  [Parameter(Mandatory=$True,Position=0)]
  $Computers
)
    foreach ($computer in $Computers)
        {
           if (Test-NetConnection -ComputerName $computer -Hops 1 -InformationLevel Quiet -ErrorAction SilentlyContinue -WarningAction SilentlyContinue)
                {
                    if (Test-Path -Path \\$computer\c$\Windows\System32\GroupPolicy\Machine\Registry.pol -ErrorAction SilentlyContinue -WarningAction SilentlyContinue)
                    {
                        $regpol= Get-Childitem \\$computer\c$\Windows\System32\GroupPolicy\Machine\Registry.pol
                        if ($regpol.LastWriteTime -lt (get-date).AddDays(-1))
                            {
                               Write-Host "$computer Registry.pol file is old ("$regpol.LastWriteTime"), deleting and forcing a GPUpdate" -ForegroundColor Magenta
                               Remove-Item $regpol
                               Invoke-WmiMethod -Name create -Path win32_process -ArgumentList "gpupdate /target:Computer /force /wait:0" -AsJob -ComputerName $computer | out-null
                            }
                        else
                        {
                            Write-Host "$computer Registry.pol file is healthy ("$regpol.LastWriteTime")" -ForegroundColor Green
                        }        
                    }
                    elseif (Test-Path -Path \\$computer\c$\Windows\System32\GroupPolicy\Machine\ -ErrorAction SilentlyContinue -WarningAction SilentlyContinue)
                    {
                        Write-Host "$computer doesn't have a Registry.pol file, forcing a GPUpdate" -ForegroundColor Magenta
                        Invoke-WmiMethod -Name create -Path win32_process -ArgumentList "gpupdate /target:Computer /force /wait:0" -AsJob -ComputerName $computer | out-null
                    }
                    
                    else
                    {
                        Write-Warning "$computer does not have c:\Windows\System32\GroupPolicy\Machine\ or you don't have access"
                    }
                }  
            else
                {
                    Write-Warning "Unable to find or contact $computer"
                }
        }