Note: The XX values represent variable bytes that change depending on the minor build version. Ensure you use a reputable, updated patching tool or verify your specific build's hex values on developer forums before applying the change. Step 5: Restart the Remote Desktop Service
Modifying core system files breaches Microsoft's End User License Agreement (EULA). This practice can cause severe operational issues in production environments.
: A more stable method that doesn't modify the actual DLL on disk. Instead, it loads a layer between the Service Control Manager and Remote Desktop Services to intercept calls and "trick" the system into allowing more sessions.
The phrase tells a fascinating story of platform hardening. What began as a simple byte‑hack to bypass an RDP session limit evolved into an arms race. Microsoft, through cumulative updates, introduced multiple layers of integrity checking, digital signature validation, and distributed licensing enforcement. The result: those who previously relied on a patched termsrv.dll found themselves locked out after applying official updates. windows server 2019 termsrvdll patch patched
Patching requires careful handling of system files. The process generally involves stopping the Terminal Services service, replacing the DLL, and restarting the service. 1. Preparation
Set "Limit number of connections" to enabled and set it to a higher number (e.g., 999999)
Once found, the tool replaces this sequence with a new one. A typical replacement is B8 00 01 00 00 89 81 38 06 00 00 90 , which effectively tells the system to always "return success" for the session-limit check, thereby disabling the limit. Note: The XX values represent variable bytes that
takeown /f C:\Windows\System32\termsrv.dll /a icacls C:\Windows\System32\termsrv.dll /grant Administrators:F Use code with caution. Step 3: Create a Secure Backup
Windows protects system files by assigning ownership to the TrustedInstaller account. You must change ownership to the Administrators group. Open Command Prompt as an Administrator. Run the following command to take ownership: takeown /f C:\Windows\System32\termsrv.dll /a Use code with caution.
Before modifying critical system binaries, ensure you understand the risks and meet the operational requirements. Technical Prerequisites This practice can cause severe operational issues in
: A more modular alternative that doesn't modify the termsrv.dll file directly. Instead, it loads between the Service Control Manager and Terminal Services to "trick" the system into allowing more sessions.
(The /y switch automatically stops dependent services like the Remote Desktop Services UserMode Port Redirector). Step 2: Take Ownership and Grant Permissions
"Another user is signed in. If you continue, they’ll be disconnected. Do you want to sign in anyway?"
While patching termsrv.dll solves an immediate technical limitation, deploying it in a production environment carries significant risks. 1. Licensing Violations
Patching termsrv.dll for Multiple RDP Sessions on Windows Server 2019