Guide to Windows Server 2025 Upgrades from Windows Server 2012 R2 & 2016 2019

<#
.SYNOPSIS
    Windows Server 2025 In-Place Upgrade Readiness Assessment Script.
.DESCRIPTION
    This script performs a series of checks to assess if a server meets the key requirements
    for an in-place upgrade to Windows Server 2025. It checks hardware, system health,
    and common configuration blockers.
.NOTES
    Author: Technical Report AI
    Version: 1.1
    Run this script with Administrator privileges.
#>

#region --- Script Configuration ---
$logFile = "C:TempUpgradeReadiness-$(Get-Date -Format 'yyyyMMdd-HHmmss').log"
$requiredFreeSpaceGB = 60 # Increased from minimum for safety
$requiredRamGB = 4 # Minimum recommended for Desktop Experience
#endregion

#region --- Helper Functions ---
function Write-Log {
    param(
        [string]$Message,
        [string]$Color = "White"
    )
    Write-Host $Message -ForegroundColor $Color
    Add-Content -Path $logFile -Value "$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss') - $Message"
}
#endregion

#region --- Main Script Logic ---
if (-not (Test-Path (Split-Path $logFile))) { New-Item -ItemType Directory -Path (Split-Path $logFile) -Force | Out-Null }
"--- Windows Server 2025 Upgrade Readiness Check ---" | Out-File $logFile

Write-Log "--- Section 1: System Information ---" "Cyan"
Get-ComputerInfo -Property WindowsProductName, WindowsEditionId, OsHardwareAbstractionLayer, CsTotalPhysicalMemory, CsProcessors | Format-List | Out-File -FilePath $logFile -Append

Write-Log "--- Section 2: Hardware Validation ---" "Cyan"
$arch = (Get-CimInstance -ClassName Win32_Processor).AddressWidth
if ($arch -eq 64) { Write-Log " [PASS] Processor Architecture: 64-bit" "Green" } 
else { Write-Log "[FAIL] Processor Architecture: $($arch)-bit. A 64-bit processor is required." "Red" }

$totalRamGB = [math]::Round((Get-CimInstance -ClassName Win32_ComputerSystem).TotalPhysicalMemory / 1GB)
if ($totalRamGB -ge $requiredRamGB) { Write-Log " [PASS] Installed RAM: $($totalRamGB) GB (Requirement: >= $($requiredRamGB) GB)" "Green" }
else { Write-Log "[FAIL] Installed RAM: $($totalRamGB) GB (Requirement: >= $($requiredRamGB) GB)" "Red" }

$systemDrive = Get-CimInstance -ClassName Win32_LogicalDisk | Where-Object { $_.DeviceID -eq $env:SystemDrive }
$freeSpaceGB = [math]::Round($systemDrive.FreeSpace / 1GB)
if ($freeSpaceGB -ge $requiredFreeSpaceGB) { Write-Log " [PASS] System Drive Free Space: $($freeSpaceGB) GB (Requirement: >= $($requiredFreeSpaceGB) GB)" "Green" }
else { Write-Log "[FAIL] System Drive Free Space: $($freeSpaceGB) GB (Requirement: >= $($requiredFreeSpaceGB) GB)" "Red" }

try {
    $tpm = Get-Tpm
    if ($tpm.TpmPresent) {
        if ($tpm.SpecificationVersion -match "^2.0") { Write-Log " [PASS] TPM 2.0 is present and ready." "Green" }
        else { Write-Log "[WARN] TPM is present but is not version 2.0 (Version: $($tpm.SpecificationVersion))." "Yellow" }
    } else { Write-Log "[WARN] TPM is not present. Required for some security features." "Yellow" }
} catch { Write-Log "[INFO] Could not query TPM status. Manual verification required." "Gray" }

try {
    if (Confirm-SecureBootUEFI) { Write-Log " [PASS] Secure Boot is enabled." "Green" }
    else { Write-Log "[FAIL] Secure Boot is not enabled or BIOS is not in UEFI mode." "Red" }
} catch { Write-Log "[WARN] Could not determine Secure Boot status. Requires UEFI firmware." "Yellow" }

Write-Log "--- Section 3: System Health and Configuration ---" "Cyan"
$pendingReboot = (Get-ItemProperty "HKLM:SOFTWAREMicrosoftWindowsCurrentVersionWindowsUpdateAuto UpdateRebootRequired" -ErrorAction SilentlyContinue) -or (Get-Item "HKLM:SYSTEMCurrentControlSetControlSession Manager" -ErrorAction SilentlyContinue | Get-ItemProperty -Name PendingFileRenameOperations -ErrorAction SilentlyContinue)
if (-not $pendingReboot) { Write-Log " [PASS] No pending reboot detected." "Green" }
else { Write-Log "[FAIL] A pending reboot is required. Please restart the server before proceeding." "Red" }

$bootFromVHD = (Get-ItemProperty "HKLM:SYSTEMCurrentControlSetControl" -Name "PEFirmwareType" -ErrorAction SilentlyContinue)
if (-not $bootFromVHD) { Write-Log " [PASS] Server does not appear to be configured for Boot from VHD." "Green" }
else { Write-Log "[FAIL] Boot from VHD is configured and is not supported for in-place upgrades." "Red" }

$sqlService = Get-Service -Name "MSSQL*" -ErrorAction SilentlyContinue
if ($sqlService) { Write-Log "[WARN] SQL Server instance(s) detected. Manually verify all versions are compatible with WS2025." "Yellow" }
else { Write-Log " [PASS] No standard SQL Server services detected." "Green" }

Write-Log "--- Readiness Check Complete ---" "Cyan"
Write-Log "Log file saved to: $logFile" "Cyan"

.setup.exe /auto upgrade /quiet /imageindex 4 /DynamicUpdate disable /Compat IgnoreWarning /eula accept /copylogs C:TempSetupLogs