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Updated AUTO LKGC script for better logging and structure TOOLING 59898 #118

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Updated AUTO LKGC script for better logging and structure TOOLING 59898 #118

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157 changes: 81 additions & 76 deletions src/windows/win-LKGC.ps1
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Original file line number Diff line number Diff line change
@@ -1,89 +1,94 @@
# Welcome to the AUTO LKGC(Last Known Good Configuration) by Daniel Muñoz L!
# Contact me Daniel Muñoz L : damunozl@microsoft.com if questions.
# .SUMMARY
# Last Known Good Configuration enabler offline from rescue VM.
# Increment Last Known Good Configuration registry values by 1.
# Public docs: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/start-vm-last-known-good,
# https://support.microsoft.com/en-us/topic/you-receive-error-stop-error-code-0x0000007b-inaccessible-boot-device-after-you-install-windows-updates-7cc844e4-4daf-a71c-cd23-f99b50d53e31
#
# .RESOLVES
# If Windows is not booting correctly due to recently installed software or related changes, modifying the LKGC values
# can revert the changes to attempt a successful boot.
# If you've recently installed new software or changed some Windows settings, and your Azure Windows virtual machine (VM) stops booting correctly,
# you might have to start the VM by using the Last Known Good Configuration for troubleshooting.
<#
.SYNOPSIS
Enables Last Known Good Configuration (LKGC) and logs registry state changes.
Increment Last Known Good Configuration registry values by 1.
Public docs: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/windows/start-vm-last-known-good, # https://support.microsoft.com/en-us/topic/you-receive-error-stop-error-code-0x0000007b-inaccessible-boot-device-after-you-install-windows-updates-7cc844e4-4daf-a71c-cd23-f99b50d53e31

.RESOLVES
If Windows is not booting correctly due to recently installed software or related changes, modifying the LKGC values
can revert the changes to attempt a successful boot.
If you've recently installed new software or changed some Windows settings, and your Azure Windows virtual machine (VM) stops booting correctly,
you might have to start the VM by using the Last Known Good Configuration for troubleshooting.
Created by Tony.Mocanu@Microsoft.com
#>

out-null
cmd /c color 0A
$host.UI.RawUI.WindowTitle = " --== AUTO LKGC by Daniel Muñoz L ==--"
# 1. Import common logic
. .\src\windows\common\setup\init.ps1
. .\src\windows\common\helpers\Get-Disk-Partitions.ps1

# Rescue OS variable
$diska='c'
$logFile = "$env:SystemDrive\Repair-LKGC.log"

# Finder for faulty OS letter
$diskarray = "d","q","w","e","r","t","y","u","i","o","p","s","f","g","h","j","k","l","z","x","v","n","m"
$diskb="000"
foreach ($diskt in $diskarray)
{
if (Test-Path -Path "$($diskt):\Windows")
{
$diskb=$diskt
}
}
try {
Log-Info "Starting AUTO LKGC Script..." | Tee-Object -FilePath $logFile -Append

# IN CASE OF FINDER FAILURE
if ($diskb -eq "000") {write-output "SCRIPT COULD NOT FIND A RESCUE OS DISK ATTACHED, EXITING";start-sleep 10;Exit}
# 2. Finder for faulty OS letter
$diskb = "000"
$diskarray = "d","q","w","e","r","t","y","u","i","o","p","s","f","g","h","j","k","l","z","x","v","n","m"
foreach ($diskt in $diskarray) {
if (Test-Path -Path "$($diskt):\Windows") { $diskb = $diskt; break }
}

# OS VER PEEK
reg.exe load "HKLM\BROKENSYSTEM" "$($diskb):\Windows\System32\config\software"
Start-sleep 3
(Get-ItemProperty -path 'registry::hklm\BROKENSYSTEM\microsoft\windows nt\currentversion').ProductName | %{ [int]$winosver=$_.Split(' ')[1]; }
(Get-ItemProperty -path 'registry::hklm\BROKENSYSTEM\microsoft\windows nt\currentversion').ProductName | %{ [int]$winosver=$_.Split(' ')[2]; }
reg.exe unload "HKLM\BROKENSYSTEM"
Start-sleep 3
if ($diskb -eq "000") {
Log-Error "SCRIPT COULD NOT FIND A RESCUE OS DISK ATTACHED" | Tee-Object -FilePath $logFile -Append
return $STATUS_ERROR
}

# Hive loader into rescue VM
reg.exe load "HKU\BROKENSYSTEM" "$($diskb):\Windows\System32\config\SYSTEM"
Start-sleep 3
# 3. OS Version Peek
reg.exe load "HKLM\BROKENSYSTEM" "$($diskb):\Windows\System32\config\software"
Start-Sleep -Seconds 2
$productName = (Get-ItemProperty -path 'registry::hklm\BROKENSYSTEM\microsoft\windows nt\currentversion').ProductName
$winosver = 0
if ($productName -match '(\d+)') { $winosver = [int]$matches[1] }
reg.exe unload "HKLM\BROKENSYSTEM"

# Acquiring reg values
$currentreg = (Get-ItemProperty -path Registry::HKU\BROKENSYSTEM\Select).current
$defaultreg = (Get-ItemProperty -path Registry::HKU\BROKENSYSTEM\Select).default
$failedreg = (Get-ItemProperty -path Registry::HKU\BROKENSYSTEM\Select).failed
$lkgcreg = (Get-ItemProperty -path Registry::HKU\BROKENSYSTEM\Select).LastKnownGood
# 4. Hive loader
Log-Info "Loading System hive from $($diskb):..." | Tee-Object -FilePath $logFile -Append
reg.exe load "HKU\BROKENSYSTEM" "$($diskb):\Windows\System32\config\SYSTEM"
Start-Sleep -Seconds 2

# FILTER IF LKGC IS ALREADY THERE FOR Windows 10, Windows Server 2016, and newer versions.
if (($winosver -eq 10) -or ($winosver -ge 2016))
{
if ($currentreg -ge 2) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($defaultreg -ge 2) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($failedreg -ge 1) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($lkgcreg -ge 2) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
}
# 5. Capture "BEFORE" State
$selectPath = "Registry::HKU\BROKENSYSTEM\Select"
$before = Get-ItemProperty -path $selectPath
Log-Info "REGISTRY STATE [BEFORE]: Current=$($before.current), Default=$($before.default), Failed=$($before.failed), LKG=$($before.LastKnownGood)" | Tee-Object -FilePath $logFile -Append

# FILTER IF LKGC IS ALREADY THERE FOR Windows Server 2012 version.
if ($winosver -eq 2012)
{
# CHECK IF LKGC IS ALREADY THERE AND EXIT IF SO
if ($currentreg -ge 2) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($defaultreg -ge 2) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($failedreg -ge 1) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
elseif ($lkgcreg -ge 3) {reg.exe unload "HKU\BROKENSYSTEM";write-output "LKGC WAS ALREADY SET, NO CHANGES DONE";start-sleep 5;exit}
}
# 6. Logic Filter
$alreadySet = $false
if (($winosver -eq 10) -or ($winosver -ge 2016)) {
if (($before.current -ge 2) -or ($before.default -ge 2) -or ($before.failed -ge 1) -or ($before.LastKnownGood -ge 2)) { $alreadySet = $true }
}
elseif ($winosver -eq 2012) {
if (($before.current -ge 2) -or ($before.default -ge 2) -or ($before.failed -ge 1) -or ($before.LastKnownGood -ge 3)) { $alreadySet = $true }
}

if ($alreadySet) {
reg.exe unload "HKU\BROKENSYSTEM"
Log-Warning "LKGC WAS ALREADY SET, NO CHANGES DONE" | Tee-Object -FilePath $logFile -Append
return $STATUS_SUCCESS
}

# Plus 1
$currentreg = $currentreg+1
$defaultreg = $defaultreg+1
$failedreg = $failedreg+1
$lkgcreg = $lkgcreg+1
# 7. Apply Changes
Log-Info "Applying LKGC increments..." | Tee-Object -FilePath $logFile -Append
Set-Itemproperty -path $selectPath -Name 'current' -Type DWORD -value ($before.current + 1)
Set-Itemproperty -path $selectPath -Name 'default' -Type DWORD -value ($before.default + 1)
Set-Itemproperty -path $selectPath -Name 'failed' -Type DWORD -value ($before.failed + 1)
Set-Itemproperty -path $selectPath -Name 'LastKnownGood' -Type DWORD -value ($before.LastKnownGood + 1)

# ENABLING LKGC
Set-Itemproperty -path Registry::HKU\BROKENSYSTEM\Select -Name 'current' -Type DWORD -value $currentreg
Set-Itemproperty -path Registry::HKU\BROKENSYSTEM\Select -Name 'default' -Type DWORD -value $defaultreg
Set-Itemproperty -path Registry::HKU\BROKENSYSTEM\Select -Name 'failed' -Type DWORD -value $failedreg
Set-Itemproperty -path Registry::HKU\BROKENSYSTEM\Select -Name 'LastKnownGood' -Type DWORD -value $lkgcreg
# 8. Capture "AFTER" State
$after = Get-ItemProperty -path $selectPath
Log-Info "REGISTRY STATE [AFTER]: Current=$($after.current), Default=$($after.default), Failed=$($after.failed), LKG=$($after.LastKnownGood)" | Tee-Object -FilePath $logFile -Append

# Unload Hive
reg.exe unload "HKU\BROKENSYSTEM"
# 9. Cleanup
reg.exe unload "HKU\BROKENSYSTEM"
Log-Output "SCRIPT FINISHED PROPERLY, LKGC APPLIED" | Tee-Object -FilePath $logFile -Append
return $STATUS_SUCCESS

write-output " --------------- SCRIPT FINISHED PROPERLY, LKGC APPLIED --------------- "
start-sleep 10
}
catch {
Log-Error "An unexpected error occurred: $($_.Exception.Message)" | Tee-Object -FilePath $logFile -Append
reg.exe unload "HKU\BROKENSYSTEM" 2>$null
reg.exe unload "HKLM\BROKENSYSTEM" 2>$null
return $STATUS_ERROR
}
finally {
Log-Info "Script execution ended at $(Get-Date)" | Tee-Object -FilePath $logFile -Append
}