Steam VAC Repair Scripts for Windows & Linux

#!/usr/bin/env bash
# ============================================================================
#  Steam / VAC Repair Script for Linux
#  Fixes "You cannot play on secure servers" / VAC errors in CS2 and other
#  VAC-secured games, then verifies CS2's game files automatically.
#
#  Works with the native Steam package and the Flatpak version of Steam.
#  Run it as your normal user, NOT with sudo. It asks for sudo itself only
#  if your clock needs fixing.
#
#  Usage:   chmod +x steam-vac-repair-linux.sh
#           ./steam-vac-repair-linux.sh
#
#  Use at your own risk. When in doubt, follow Valve's directions instead.
#  Loren Tedford | https://LorenTedford.com
# ============================================================================

set -u

# CS2's Steam app ID. Change this to repair a different game (e.g. 440 = TF2).
APPID=730

bold=$(tput bold 2>/dev/null || true)
reset=$(tput sgr0 2>/dev/null || true)

step()  { printf '\n%s[%s] %s%s\n' "$bold" "$1" "$2" "$reset"; }
info()  { printf '      %s\n' "$*"; }
ask()   {  # ask "Question" -> returns 0 for yes, 1 for no
    local reply
    while true; do
        read -r -p "      $1 [y/n]: " reply || return 1   # no input = no
        case "${reply,,}" in
            y|yes) return 0 ;;
            n|no)  return 1 ;;
        esac
    done
}

if [ "$(id -u)" -eq 0 ]; then
    echo "Please run this script as your normal user, not with sudo or as root."
    echo "Steam is installed per user, so running as root would repair the wrong account."
    exit 1
fi

# ---------------------------------------------------------------------------
# Detect how Steam is installed
# ---------------------------------------------------------------------------
STEAM_KIND=""
if command -v flatpak >/dev/null 2>&1 && flatpak info com.valvesoftware.Steam >/dev/null 2>&1; then
    STEAM_KIND="flatpak"
fi
if command -v steam >/dev/null 2>&1; then
    # Prefer native if both are present and the native data folder exists
    if [ -z "$STEAM_KIND" ] || [ -d "$HOME/.local/share/Steam" ] || [ -d "$HOME/.steam/steam" ]; then
        STEAM_KIND="native"
    fi
fi
if [ -z "$STEAM_KIND" ] && command -v snap >/dev/null 2>&1 && snap list steam >/dev/null 2>&1; then
    STEAM_KIND="snap"
fi

if [ -z "$STEAM_KIND" ]; then
    echo "Could not find Steam (checked native, Flatpak and Snap)."
    exit 1
fi

steam_cmd() {
    case "$STEAM_KIND" in
        native)  steam "$@" ;;
        flatpak) flatpak run com.valvesoftware.Steam "$@" ;;
        snap)    snap run steam "$@" ;;
    esac
}

# Find the Steam data folder
STEAM_DIR=""
for d in \
    "$HOME/.var/app/com.valvesoftware.Steam/.local/share/Steam" \
    "$HOME/snap/steam/common/.local/share/Steam" \
    "$HOME/.local/share/Steam" \
    "$HOME/.steam/steam" \
    "$HOME/.steam/debian-installation"; do
    if [ -d "$d/steamapps" ] || [ -d "$d/userdata" ]; then
        case "$STEAM_KIND:$d" in
            flatpak:*/.var/app/*|snap:*/snap/steam/*|native:"$HOME"/.local/*|native:"$HOME"/.steam/*)
                STEAM_DIR="$d"; break ;;
        esac
    fi
done

clear 2>/dev/null || true
echo "============================================================"
echo "  Steam VAC Repair Script for Linux"
echo "  Loren Tedford | https://LorenTedford.com"
echo "============================================================"
echo
echo "  Steam type:   $STEAM_KIND"
echo "  Steam folder: ${STEAM_DIR:-not found (some checks will be skipped)}"
echo
echo "  This script will:"
echo "    1. Close CS2 and Steam"
echo "    2. Check for software that can cause VAC errors"
echo "    3. Check that your clock is synced"
echo "    4. (Optional) Reset Steam's app cache"
echo "    5. Start Steam and verify CS2's game files"
echo
if ! ask "Start the repair?"; then
    exit 0
fi

# ---------------------------------------------------------------------------
# 1. Close CS2 and Steam
# ---------------------------------------------------------------------------
step "1/5" "Closing CS2 and Steam..."
pkill -x cs2 2>/dev/null || true
if pgrep -x steam >/dev/null 2>&1 || pgrep -f 'steamwebhelper' >/dev/null 2>&1; then
    steam_cmd -shutdown >/dev/null 2>&1 &
    info "Waiting for Steam to close..."
    for _ in $(seq 1 30); do
        pgrep -x steam >/dev/null 2>&1 || break
        sleep 1
    done
    if pgrep -x steam >/dev/null 2>&1; then
        info "Steam didn't close on its own. Stopping it."
        pkill -x steam 2>/dev/null || true
        sleep 2
    fi
fi
pkill -f steamwebhelper 2>/dev/null || true
info "Done."

# ---------------------------------------------------------------------------
# 2. Check for software that can cause VAC errors (report only)
# ---------------------------------------------------------------------------
step "2/5" "Checking for software that can cause VAC errors..."
FOUND=0
for p in cheatengine scanmem GameConqueror ArchiSteamFarm steam-idle idle_master; do
    if pgrep -if "$p" >/dev/null 2>&1; then
        info "FOUND RUNNING: $p"
        FOUND=1
    fi
done
[ "$FOUND" -eq 0 ] && info "No known problem programs running."

# Programs injected into the game through launch options (LD_PRELOAD etc.)
if [ -n "$STEAM_DIR" ] && [ -d "$STEAM_DIR/userdata" ]; then
    hits=$(grep -il 'LD_PRELOAD' "$STEAM_DIR"/userdata/*/config/localconfig.vdf 2>/dev/null || true)
    if [ -n "$hits" ]; then
        info ""
        info "WARNING: A game's launch options use LD_PRELOAD. Programs injected"
        info "this way can be flagged as incompatible with VAC. In Steam, right-"
        info "click CS2 > Properties > General and check LAUNCH OPTIONS. Remove"
        info "anything that loads extra libraries into the game."
    fi
fi
if [ -n "${LD_PRELOAD:-}" ]; then
    info ""
    info "WARNING: LD_PRELOAD is set in your session: $LD_PRELOAD"
    info "Anything in it is loaded into every game. Remove it before playing."
fi

# ---------------------------------------------------------------------------
# 3. Check the clock (a wrong clock can break the VAC connection)
# ---------------------------------------------------------------------------
step "3/5" "Checking that your clock is synced..."
if command -v timedatectl >/dev/null 2>&1; then
    synced=$(timedatectl show -p NTPSynchronized --value 2>/dev/null || echo "unknown")
    ntp_on=$(timedatectl show -p NTP --value 2>/dev/null || echo "unknown")
    if [ "$synced" = "yes" ]; then
        info "Clock is synced."
    else
        info "Clock is NOT confirmed synced (NTP service: $ntp_on)."
        if ask "Turn on automatic time sync now? (uses sudo)"; then
            if sudo timedatectl set-ntp true; then
                info "Automatic time sync turned on. It may take a minute to sync."
            else
                info "Could not turn on time sync. Check your desktop's Date & Time settings."
            fi
        fi
    fi
else
    info "timedatectl not available. Check your Date & Time settings are set to automatic."
fi

# ---------------------------------------------------------------------------
# 4. Optional: reset Steam's app cache (it's rebuilt automatically)
# ---------------------------------------------------------------------------
step "4/5" "Reset Steam's app cache?"
info "This clears Steam's cached game info. Nothing is deleted; the old"
info "folder is renamed to a backup, and Steam rebuilds it when it starts."
if [ -n "$STEAM_DIR" ] && [ -d "$STEAM_DIR/appcache" ]; then
    if ask "Reset the app cache?"; then
        backup="$STEAM_DIR/appcache.bak-$(date +%Y%m%d-%H%M%S)"
        if mv "$STEAM_DIR/appcache" "$backup"; then
            info "Moved to: $backup"
            info "You can delete that backup once everything works."
        else
            info "Could not rename the app cache. Skipping."
        fi
    else
        info "Skipped."
    fi
else
    info "App cache folder not found. Skipping."
fi

# ---------------------------------------------------------------------------
# 5. Start Steam and verify CS2's game files
# ---------------------------------------------------------------------------
step "5/5" "Starting Steam and verifying CS2 game files..."
nohup bash -c "$(declare -f steam_cmd); STEAM_KIND='$STEAM_KIND'; steam_cmd 'steam://validate/$APPID'" >/dev/null 2>&1 &
disown 2>/dev/null || true
info "Steam will open and check CS2's files. Watch the Downloads page"
info "in Steam until it finishes."

echo
echo "============================================================"
echo "  Repair finished."
echo
echo "  If the error comes back:"
echo "    - Run CS2 natively. In Steam: right-click CS2 > Properties >"
echo "      Compatibility, and make sure Proton is NOT forced."
echo "    - Remove skin changers, custom textures and anything in"
echo "      CS2's launch options that injects into the game"
echo "    - Restart your PC, then try again"
echo "    - See the directions page for more help"
echo
echo "  Loren Tedford | https://LorenTedford.com"
echo "============================================================"