Mass-validate all Steam games on Windows

Validate-Steam-Games.ps1

########################################################################################################################
# Mass Steam Game Validator
#
# This script, meant to be used on Windows, validates whole Steam libraries. By default, Steam client can only do it
# one-by-one which is cumbersome in larger libraries. This tool uses the Valve's official steamCMD.
# The tool, by default, will attempt to validate all games in all libraries found, using the default account. Use -Help
# to see available options.
#
# To run this tool, save it as ".ps1" file, start Windows PowerShell/Windows Terminal, and type
# .\Validate-Steam-Games.ps1 in the console. You may need to enable PS scripts (https://superuser.com/a/106362) first.
#
# License: MIT; (c) Gregory House (https://github.com/kiler129)

param (
    [switch]$DryRun,
    [string]$Skip,
    [switch]$Help,
    [string]$LibraryPath,
    [string]$User,
    [switch]$Verbose
)

# --- Help ---
if ($Help) {
    $scriptName = $MyInvocation.MyCommand.Name
    Write-Host "Mass Steam Game Validator" -ForegroundColor Yellow
    Write-Host ""
    Write-Host "USAGE:" -ForegroundColor Cyan
    Write-Host "  .\$scriptName [-DryRun] [-Skip <AppIDs>] [-LibraryPath <Path>] [-User <Name>] [-Verbose] [-Help]" -ForegroundColor White
    Write-Host ""
    Write-Host "OPTIONS:" -ForegroundColor Cyan
    Write-Host "  -DryRun              Verifies Steam login and lists games, but does not validate them." -ForegroundColor White
    Write-Host "  -Skip <IDs>          Comma-separated AppIDs to skip (e.g. -Skip 346110,123456)." -ForegroundColor White
    Write-Host "  -LibraryPath <Path>  Use a specific Steam library root (folder containing 'steamapps')." -ForegroundColor White
    Write-Host "                       If omitted, libraries are auto-detected from registry and libraryfolders.vdf." -ForegroundColor White
    Write-Host "  -User <Name>         Steam username to use. If omitted, auto-detected from loginusers.vdf (or prompted)." -ForegroundColor White
    Write-Host "  -Verbose             Echo the exact steamcmd command and stream its live output." -ForegroundColor White
    Write-Host "  -Help                Show this help screen and exit." -ForegroundColor White
    exit
}

# --- Parse Skip list ---
$skipList = @()
if ($Skip) {
    $skipList = $Skip.Split(",") | ForEach-Object { $_.Trim() } | Where-Object { $_ }
    if ($skipList.Count) { Write-Host "[INFO] Will skip AppIDs: $($skipList -join ', ')" -ForegroundColor Yellow }
}

# --- Steam install path ---
$steamReg = Get-ItemProperty -Path "HKCU:\Software\Valve\Steam" -ErrorAction SilentlyContinue
if (-not $steamReg -or -not $steamReg.SteamPath) {
    Write-Host "[ERROR] Could not find Steam in registry." -ForegroundColor Red
    $steamPath = Read-Host "Enter your Steam install path (e.g. C:\Program Files (x86)\Steam)"
} else {
    $steamPath = $steamReg.SteamPath
}
$libraryFile    = Join-Path $steamPath "steamapps\libraryfolders.vdf"
$loginUsersFile = Join-Path $steamPath "config\loginusers.vdf"

# --- Detect usernames from loginusers.vdf ---
function Detect-SteamUsers {
    $users = @()
    if (Test-Path -LiteralPath $loginUsersFile) {
        $content = Get-Content -LiteralPath $loginUsersFile -Raw
        $rx = '"AccountName"\s*"([^"]+)"'
        $matches = [regex]::Matches($content, $rx)
        foreach ($m in $matches) { $users += $m.Groups[1].Value }
    }
    $users | Where-Object { $_ -and $_.Trim() -ne '' } | Select-Object -Unique
}
$detectedUsers = Detect-SteamUsers

# --- Resolve steamcmd ---
function Resolve-SteamCmd {
    $cmd = Get-Command steamcmd -ErrorAction SilentlyContinue
    if ($cmd) {
        Write-Host "[INFO] Found steamcmd in PATH." -ForegroundColor Green
        return "steamcmd"
    }

    Write-Host "[ERROR] steamcmd not found in PATH." -ForegroundColor Red
    if (Get-Command winget -ErrorAction SilentlyContinue) {
        Write-Host "Install it with:" -ForegroundColor Cyan
        Write-Host "    winget install steamcmd" -ForegroundColor White
    } else {
        Write-Host "Download: https://developer.valvesoftware.com/wiki/SteamCMD" -ForegroundColor Cyan
    }

    $choice = Read-Host "Do you want to manually enter the path now? (Y/N)"
    if ($choice -notmatch '^[Yy]$') { throw "steamcmd is required but not installed or provided." }

    while ($true) {
        $candidate = Read-Host "Enter full path to steamcmd.exe (or Ctrl+C to cancel)"
        if ([string]::IsNullOrWhiteSpace($candidate)) { Write-Host "[WARN] Path cannot be empty." -ForegroundColor Yellow; continue }
        $candidate = $candidate.Trim('"')
        if (-not (Test-Path -LiteralPath $candidate)) { Write-Host "[ERROR] File not found: $candidate" -ForegroundColor Red; continue }
        try {
            & $candidate +quit | Out-Null
            if ($LASTEXITCODE -eq 0) { Write-Host "[INFO] steamcmd verified at: $candidate" -ForegroundColor Green; return $candidate }
            Write-Host "[ERROR] steamcmd exited with code $LASTEXITCODE when tested." -ForegroundColor Red
        } catch { Write-Host "[ERROR] Failed to run steamcmd: $($_.Exception.Message)" -ForegroundColor Red }
    }
}

# --- Resolve username ---
function Resolve-SteamUser {
    param([string]$UserOverride, [string[]]$Detected)

    if (-not [string]::IsNullOrWhiteSpace($UserOverride)) {
        Write-Host "[INFO] Using specified Steam user: $UserOverride" -ForegroundColor Green
        return $UserOverride
    }
    if ($Detected.Count -eq 1) {
        Write-Host "[INFO] Auto-detected Steam user: $($Detected[0])" -ForegroundColor Green
        return $Detected[0]
    }
    if ($Detected.Count -gt 1) {
        Write-Host "[INFO] Multiple Steam users detected:" -ForegroundColor Yellow
        for ($i = 0; $i -lt $Detected.Count; $i++) {
            Write-Host " [$i] $($Detected[$i])"
        }
        while ($true) {
            $choice = Read-Host "Select user number"
            if ($choice -match '^\d+$' -and [int]$choice -ge 0 -and [int]$choice -lt $Detected.Count) {
                $selected = $Detected[[int]$choice]
                Write-Host "[INFO] Selected Steam user: $selected" -ForegroundColor Green
                return $selected
            }
            Write-Host "[WARN] Invalid choice, try again." -ForegroundColor Yellow
        }
    }
    Write-Host "[WARN] No Steam usernames detected in loginusers.vdf." -ForegroundColor Yellow
    $manual = Read-Host "Enter your Steam username"
    Write-Host "[INFO] Using manually entered Steam user: $manual" -ForegroundColor Green
    return $manual
}

# --- Test login (interactive always) ---
function Test-SteamLogin {
    param([string]$SteamCmdPath, [string]$SteamUser, [switch]$Verbose)

    Write-Host "[INFO] Testing Steam login for user '$SteamUser'..." -ForegroundColor Cyan
    Write-Host "       If cached credentials are missing, SteamCMD will ask for your password/Steam Guard." -ForegroundColor Yellow
    Write-Host "       This prompt is from the official Steam tool, not from this script." -ForegroundColor Yellow

    $args = @("+login", $SteamUser, "+quit")
    if ($Verbose) { Write-Host "[VERBOSE] Executing: $SteamCmdPath $($args -join ' ')" -ForegroundColor Magenta }

    & $SteamCmdPath @args
    $exit = $LASTEXITCODE

    if ($exit -eq 0) {
        Write-Host "[INFO] Steam login successful." -ForegroundColor Green
    } else {
        Write-Host "[ERROR] Steam login failed with exit code $exit." -ForegroundColor Red
        throw "Steam login failed. Cannot proceed."
    }
}

# --- Steam libraries (return roots, not steamapps) ---
function Get-SteamLibraries {
    param([string]$ManualPath)

    if ($ManualPath) { return ,$ManualPath }

    $libs = New-Object System.Collections.Generic.List[string]
    $libs.Add($steamPath)

    if (Test-Path -LiteralPath $libraryFile) {
        $content = Get-Content -LiteralPath $libraryFile
        foreach ($line in $content) {
            if ($line -match '"path"\s+"(.+)"') {
                $raw = $matches[1] -replace '\\\\','\'
                try {
                    $resolved = (Resolve-Path $raw -ErrorAction SilentlyContinue)
                    if ($resolved) {
                        $libs.Add($resolved.Path)
                    } else {
                        $libs.Add($raw)
                    }
                } catch { $libs.Add($raw) }
            }
        }
    }

    $libs | ForEach-Object { $_.ToLowerInvariant() } | Sort-Object -Unique | ForEach-Object {
        try { (Resolve-Path $_).Path } catch { $_ }
    }
}

# --- Parse manifest for name and installdir ---
function Get-AppInfoFromManifest($manifestPath) {
    $name = "<Unknown>"
    $installdir = $null
    try {
        $hitName = Select-String -Path $manifestPath -Pattern '"name"\s+"([^"]+)"' -ErrorAction SilentlyContinue | Select-Object -First 1
        if ($hitName -and $hitName.Matches.Count -gt 0) { $name = $hitName.Matches[0].Groups[1].Value }
        $hitDir = Select-String -Path $manifestPath -Pattern '"installdir"\s+"([^"]+)"' -ErrorAction SilentlyContinue | Select-Object -First 1
        if ($hitDir -and $hitDir.Matches.Count -gt 0) { $installdir = $hitDir.Matches[0].Groups[1].Value }
    } catch {}
    [PSCustomObject]@{ Name = $name; InstallDir = $installdir }
}

# --- Validate one game at its real install path ---
function Validate-App([string]$appId, [string]$gameName, [string]$installPath) {
    if ($skipList -contains $appId) { Write-Host "[SKIP] $appId ($gameName)" -ForegroundColor DarkYellow; return }
    if ($DryRun) { Write-Host "[DRYRUN] Would validate $appId ($gameName) at [$installPath]" -ForegroundColor DarkCyan; return }

    if (-not (Test-Path -LiteralPath $installPath)) {
        Write-Host "[WARN] Install path not found, creating (SteamCMD may re-download): $installPath" -ForegroundColor Yellow
        New-Item -ItemType Directory -Force -Path $installPath | Out-Null
    }

    $args = @(
        "+force_install_dir", $installPath,
        "+login", $steamUser,
        "+app_update", $appId, "validate",
        "+quit"
    )

    Write-Host "[INFO] Validating $appId ($gameName) at [$installPath]..." -ForegroundColor Cyan
    if ($Verbose) { Write-Host "[VERBOSE] Executing: $steamCmdPath $($args -join ' ')" -ForegroundColor Magenta }

    & $steamCmdPath @args
    if ($LASTEXITCODE -eq 0) { Write-Host "[SUCCESS] $gameName validated." -ForegroundColor Green }
    else { Write-Host "[ERROR] $gameName failed with code $LASTEXITCODE." -ForegroundColor Red }
}

# --- Main ---
Write-Host "=======================================" -ForegroundColor Yellow
Write-Host ("Mass Steam Game Validation {0} Started: {1}" -f ($(if ($DryRun) {"(DRY RUN)"} else {""}), (Get-Date))) -ForegroundColor Yellow
Write-Host "=======================================" -ForegroundColor Yellow
Write-Host "NOTE: Validation checks files and only re-downloads missing/corrupted ones, not full reinstall." -ForegroundColor Yellow

$steamCmdPath = Resolve-SteamCmd
$steamUser    = Resolve-SteamUser -UserOverride $User -Detected $detectedUsers
Test-SteamLogin -SteamCmdPath $steamCmdPath -SteamUser $steamUser -Verbose:$Verbose

$libraries = Get-SteamLibraries -ManualPath $LibraryPath
foreach ($libRoot in $libraries) {
    $steamapps = Join-Path $libRoot "steamapps"
    if (-not (Test-Path -LiteralPath $steamapps)) {
        Write-Host "[WARN] No 'steamapps' in library: $libRoot" -ForegroundColor Yellow
        continue
    }

    Write-Host "[LIB] $libRoot" -ForegroundColor DarkYellow

    Get-ChildItem -LiteralPath $steamapps -Filter "appmanifest_*.acf" -ErrorAction SilentlyContinue |
        ForEach-Object {
            if ($_.Name -match "appmanifest_(\d+).acf") {
                $appId = $matches[1]
                $info  = Get-AppInfoFromManifest $_.FullName
                $gameName   = $info.Name
                $installdir = $info.InstallDir

                if ([string]::IsNullOrWhiteSpace($installdir)) {
                    Write-Host "[WARN] Manifest missing 'installdir' for AppID $appId; skipping to avoid mis-install." -ForegroundColor Yellow
                    return
                }

                $installPath = Join-Path (Join-Path $libRoot "steamapps\common") $installdir
                Validate-App $appId $gameName $installPath
            }
        }
}

Write-Host "=======================================" -ForegroundColor Yellow
Write-Host "Validation Completed: $(Get-Date)" -ForegroundColor Yellow
Write-Host "=======================================" -ForegroundColor Yellow

I'm wondering, have SteamCMD's command-line options changed?

Your script functions and it does validate games - but currently it seems to download the entire game again as part of the validation process. Eg: I left it run validating today for many hours, and it got up to Robocop: Rogue City. It was downloading the entire game again as part of the 'validation' (20-something gigabytes), so I cancelled out and re-opened the Steam GUI and instead validated that game directly: done in 2 minutes, without downloading more than a few megabytes.

@bickford I actually had this issue before and it was related to the script seeing a different install dir than the Steam GUI vs SteamCMD. I will have some time next week to look into that, as probably there's some edge case, or the SteamCMD intepretation changed.