#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : A Group Policy setting is not applying and gpresult does not explain why
    Fix   : Check the computer side and the WMI filter
    Source: https://jbtecwiz.com/support/srv-id-gpo-not-applying

    Run as     : Elevated PowerShell on the client
    Expect     : 30 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    A computer setting.

    HOW TO UNDO IT
    No client changes were made.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 5"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  A Group Policy setting is not applying and gpresult does not explain why' -ForegroundColor White
Write-Host '  Check the computer side and the WMI filter' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   30 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Run the report for the computer scope.' -Command {
    gpresult /r /scope:computer
    gpresult /h C:\gpo-computer.html /f /scope:computer
}

Invoke-Step -Number 2 -Do 'Test any WMI filter directly on the client -- a filter that returns nothing silently excludes the policy.' -Why 'Running the filter''s own query on the client gives an immediate yes or no. A filter that was correct when written and no longer matches -- because the OS version moved on -- is a very common cause.' -Command {
    Get-CimInstance -Query "SELECT * FROM Win32_OperatingSystem WHERE ProductType = '3'"
}

Invoke-Step -Number 3 -Do 'Check for block inheritance and enforcement on the OU chain.' -Command {
    Get-GPInheritance -Target 'OU=Servers,DC=example,DC=local' | Format-List GpoInheritanceBlocked,InheritedGpoLinks
}

Invoke-Step -Number 4 -Do 'Check the client can reach SYSVOL to read the policy files.' -Command {
    Test-Path "\\$env:USERDNSDOMAIN\SYSVOL\$env:USERDNSDOMAIN\Policies"
    Get-WinEvent -LogName 'Microsoft-Windows-GroupPolicy/Operational' -MaxEvents 30 | Format-Table TimeCreated,Id,Message -Wrap
}

Invoke-Step -Number 5 -Do 'Remember that a computer policy applies at boot. A machine that has not restarted since the policy was created will not have it.' -Manual

Write-Rule "  Confirm it worked"
Show-Prose 'The policy appears in the applied list and the setting is in place after a restart.' 'White'
Write-Host ''
if (-not $DryRun) {
    gpupdate /force /boot
    gpresult /r /scope:computer
}

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/srv-id-gpo-not-applying' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: No client changes were made.' 'DarkGray'
Write-Rule