Network Issue CS2

Disconnected by VAC: You Cannot Play on Secure Servers - CS2 Fix Guide

📅 Published: 2026-02-05 🔄 Updated: 2026-02-05 👥 Reports: 7 ⚡ Severity: 🟢 Low

🎯 Quick Answer

Perform a full Steam Service and VAC module repair by executing the Steam service repair tool and manually deleting the `steamservice.dll` and `GameOverlayRenderer.dll` files from the CS2 directory.

SECTION 1: OVERVIEW

The "Disconnected by VAC: You cannot play on secure servers" error is a termination of the game client's connection to a Valve Anti-Cheat (VAC) protected server. This error indicates the VAC system on the local machine cannot establish or maintain a secure integrity check with the game server. The error exclusively affects the Windows platform for Counter-Strike 2 (CS2) and related Source Engine titles on Steam. This error is a common occurrence, particularly on new system installations or after major Windows updates. The severity is game-breaking, as it prevents participation in matchmaking and community servers with VAC protection. The exact error message presented to the user is: "Disconnected by VAC: You cannot play on secure servers." The error often manifests mid-session, not at initial connection.

SECTION 2: SYMPTOMS

The game client operates normally for an initial period, typically 10-20 minutes into a competitive matchmaking or secure server session. The application then terminates the network connection to the game server without warning. The user is returned to the main menu or desktop with a dialog box displaying the VAC error message. Following the disconnection, subsequent attempts to reconnect to any VAC-secured server fail immediately with the same error. The matchmaking cooldown penalty is often applied. A system restart or waiting period of 30+ minutes may temporarily restore connectivity, but the error recurs in subsequent sessions. File verification through Steam does not resolve the issue.

SECTION 3: COMMON CAUSES

Category: Software Conflict Specific technical explanation: Third-party application hooks or overlays interfere with the VAC service's memory scanning and process validation routines. Common conflict sources include Discord overlay, MSI Afterburner/RivaTuner Statistics Server (RTSS), Citrix workspace applications, or legacy antivirus software with deep behavioral analysis. Why this causes the problem: VAC requires unimpeded access to game process memory and system calls. Overlays and monitoring tools inject code that can be misinterpreted by VAC as an attempt to manipulate the game. Category: Configuration Error Specific technical explanation: Corrupted or outdated Steam Client Service files, specifically steamservice.dll or GameOverlayRenderer.dll, prevent proper VAC module handshake. Why this causes the problem: The VAC system relies on these core Steam components to function. Corruption leads to failed integrity checks between the local service and the secure game server. Category: Network Problem Specific technical explanation: Router or Windows Firewall rules incorrectly block or alter UDP traffic on ports 27015-27030, 27036-27037, or TCP traffic on port 27036. Network Address Translation (NAT) or Quality of Service (QoS) settings may also disrupt the persistent connection VAC requires. Why this causes the problem: VAC uses specific outbound ports for constant, low-latency communication with Valve's servers. Packet loss or blocking on these ports causes the secure channel to time out. Category: Software Conflict Specific technical explanation: Outdated, corrupted, or incompatible graphics driver files, particularly the nvlddmkm.sys (NVIDIA) or amdkmdag.sys (AMD) kernel-mode drivers, cause memory page faults that VAC interprets as instability. Why this causes the problem: Graphics drivers operate at a kernel level. Inconsistencies in their operation can trigger VAC's detection of unstable or tampered system states. Category: Configuration Error Specific technical explanation: Incorrect system date, time, or timezone settings create a certificate validation failure for the VAC secure connection. Why this causes the problem: VAC's encrypted communication uses SSL certificates that are time-sensitive. A significant time discrepancy causes the system to reject the security certificate. Category: Software Conflict Specific technical explanation: Leftover files or registry entries from previous anti-cheat software (e.g., ESEA, Faceit) or from a previous Windows installation conflict with VAC's operation. Why this causes the problem: These remnants can create driver-level conflicts or system service interference that VAC detects as a non-standard, potentially compromised environment.

SECTION 4: SOLUTIONS

Solution 1: Repair Steam Client Service and VAC Modules

Difficulty: Easy Time Required: 10 minutes Success Rate: High Prerequisites: Administrator rights, Steam client closed. Steps:

Exit the Steam client completely via System Tray icon > Exit.
Press Windows Key + R, type cmd, then press Ctrl + Shift + Enter to launch Command Prompt as Administrator.
Execute the Steam Service repair command: "C:\Program Files (x86)\Steam\bin\SteamService.exe" /repair
Wait for the process to complete. A success message will appear.
Navigate to the CS2 directory: C:\Program Files (x86)\Steam\steamapps\common\Counter-Strike Global Offensive\game\bin\win64\
Locate and delete the following files: steamservice.dll and GameOverlayRenderer.dll.
Launch Steam normally and launch CS2. Test connectivity on a VAC-secured server.

Technical Explanation: This forces a reinstallation and registration of the core Steam Windows Service and deletes local VAC-related DLLs, which Steam will replace with fresh, verified versions upon the next launch, resolving corruption. Verification: The game connects to a VAC-secured server (e.g., official matchmaking) and remains connected for a full match duration without disconnection.

Solution 2: Configure Firewall and Network Permissions

Difficulty: Medium Time Required: 15 minutes Success Rate: High Prerequisites: Administrator rights. Steps:

Press Windows Key, type "Windows Security", and open the application.
Navigate to Firewall & network protection > Allow an app through firewall.
Click Change settings. Locate "Steam" and "Counter-Strike 2" in the list.
Ensure both Private and Public checkboxes are selected for each entry. If they are absent, click Allow another app, browse to C:\Program Files (x86)\Steam\Steam.exe and C:\Program Files (x86)\Steam\steamapps\common\Counter-Strike Global Offensive\game\bin\win64\cs2.exe, and add them with both boxes checked.
Access your router's administrative interface (typically 192.168.1.1 or 192.168.0.1).
Disable any SIP ALG (Session Initiation Protocol Application Layer Gateway) setting.
Temporarily disable any QoS (Quality of Service) or Traffic Prioritization settings.
Save settings and reboot the router.

Technical Explanation: This ensures Windows Firewall does not block VAC's outbound communication and prevents router-level network address translation features from corrupting the persistent UDP connections VAC requires. Verification: Run the command netstat -an | findstr 27015 in Command Prompt while CS2 is connected to a server. You should see ESTABLISHED or TIME_WAIT connections on ports 27015-27037.

Solution 3: Perform a Clean Boot to Isolate Software Conflicts

Difficulty: Medium Time Required: 20 minutes Success Rate: Medium Prerequisites: Administrator rights. Steps:

Press Windows Key + R, type msconfig, and press Enter.
In the System Configuration window, navigate to the Services tab.
Check the box Hide all Microsoft services, then click Disable all.
Navigate to the Startup tab and click Open Task Manager.
In Task Manager, disable every startup item.
Close Task Manager, click OK in System Configuration, and restart the PC.
After restart, launch only Steam and CS2. Do not launch Discord, Spotify, or any other third-party application.
Test CS2 on a VAC-secured server.

Technical Explanation: This starts Windows with a minimal set of drivers and startup programs, eliminating third-party software as the source of interference with VAC's system-level operations. Verification: If the error does not occur in the Clean Boot state, a third-party service is the cause. Re-enable services and startup items in groups to identify the conflict.

Solution 4: Update System Drivers and Windows

Difficulty: Easy Time Required: 15 minutes Success Rate: Medium Prerequisites: Internet connection. Steps:

Press Windows Key + X and select Device Manager.
Expand Display adapters. Right-click your GPU and select Update driver > Search automatically for drivers. Install any updates.
Expand Network adapters. Right-click your network device and select Update driver > Search automatically for drivers.
Press Windows Key + I to open Settings. Go to Windows Update and click Check for updates. Install all available updates, including optional updates under Advanced options.
After all updates, restart the computer.

Technical Explanation: Outdated network and graphics drivers contain bugs that can cause packet handling errors or memory management faults, which disrupt the stable environment VAC mandates. Verification: In Device Manager, confirm no devices have warning icons. In Windows Update settings, confirm the system is up to date with the latest cumulative update.

Solution 5: Flush DNS and Reset Windows Socket

Difficulty: Easy Time Required: 5 minutes Success Rate: Low (but critical if underlying issue exists) Prerequisites: Administrator rights. Steps:

Press Windows Key + R, type cmd, then press Ctrl + Shift + Enter to launch Command Prompt as Administrator.
Execute the following commands in order, pressing Enter after each:

- ipconfig /release - ipconfig /flushdns - ipconfig /renew - netsh winsock reset - netsh int ip reset

After the commands complete, restart the computer.

Technical Explanation: Corrupted DNS cache or Windows socket catalog entries can cause routing errors to Valve's VAC server endpoints. This resets the network stack to its default configuration. Verification: The commands execute without error. Post-restart, general network connectivity and CS2 VAC connections are tested.

Solution 6: Verify System Time and Disable Non-Essential Services

Difficulty: Advanced Time Required: 10 minutes Success Rate: Medium Prerequisites: Administrator rights. Steps:

Right-click the clock in the Windows taskbar and select Adjust date/time.
Ensure Set time automatically and Set time zone automatically are toggled On. Synchronize manually if needed.
Press Windows Key + R, type services.msc, and press Enter.
Locate the following services. Double-click each and set Startup type to Disabled if they are running:

- Citrix HDX Media Streamer for Windows User-mode - NVIDIA Stereoscopic 3D Driver Service - MSI Afterburner Service (or any RivaTuner service) - Bonjour Service

Apply changes and restart the computer.

Technical Explanation: Incorrect system time invalidates SSL certificates. Specific non-critical services are documented to hook into applications in ways that can trigger VAC's integrity checks. Verification: System time is correct to within one second. The specified services show a Status of "Stopped" and Startup type of "Disabled" in services.msc.

SECTION 5: PREVENTION

Maintain a stable system configuration by updating graphics drivers directly from NVIDIA or AMD, not through Windows Update. Configure Windows Firewall rules permanently for Steam and CS2 executables. Before major Windows feature updates, create a system restore point. Conduct a monthly verification of Steam game files for CS2. Avoid installing peripheral software that adds in-game overlays or performance monitors. Regularly clear the Steam download cache through Steam Settings > Downloads > "Clear Download Cache". Monitor the Windows Event Viewer for system errors around the time of VAC disconnections.

SECTION 6: WHEN TO CONTACT SUPPORT

Contact Steam Support only after exhaustively testing all solutions in this guide and confirming the error persists in a Clean Boot state. Prepare diagnostic information including the exact CS2 build version, Windows version and build number, and a list of all installed third-party software with overlays or kernel-level drivers. Provide the Steam\logs\ directory contents, specifically connection_log.txt and content_log.txt. Official support channels are accessed via [https://help.steampowered.com](https://help.steampowered.com). Escalation is necessary if the error indicates a hardware-level incompatibility or a compromised Windows installation.