If you are reading this, you have likely encountered one of the most common frustrations in Windows administration: the Remote Desktop Services (RDS) limitation.
You are working on a critical task on your Windows Server 2019 box. You step away for a coffee, or perhaps a colleague tries to jump on to check a log. Suddenly, you are greeted with the dreaded prompt: "The number of connections to this computer is limited and all connections are in use."
By default, Windows Server 2019 restricts Remote Desktop sessions to a single user per session (unless you purchase expensive RDS User/Device CALs and set up a Remote Desktop Session Broker). But what if you just want to allow two or three administrators to log in simultaneously without the hefty licensing fees?
Enter the termsrv.dll patch.
In this post, we dive into how this patch works, why the "Repack" versions are popular, and the step-by-step process to implement it.
If you want, I can:
Patching termsrv.dll on Windows Server 2019 is a common workaround to enable multiple concurrent RDP sessions without installing the full Remote Desktop Services (RDS) role or purchasing Client Access Licenses (CALs). Direct Method: Manual Hex Patching
To manually enable multiple sessions, you must replace a specific byte sequence within the termsrv.dll file.
Backup the Original: Open CMD as Administrator and run:copy c:\Windows\System32\termsrv.dll c:\Windows\System32\termsrv.dll.bak. Take Ownership: takeown /F c:\Windows\System32\termsrv.dll /A.
icacls c:\Windows\System32\termsrv.dll /grant Administrators:F. Stop the Service: Run net stop TermService.
Patch the File: Use a hex editor to search for the following pattern and replace it: Find: 39 81 3C 06 00 00 0F 84 XX XX XX XX Replace with: B8 00 01 00 00 89 81 38 06 00 00 90 Restart the Service: Run net start TermService. Alternative: RDP Wrapper Library
Instead of modifying the system DLL directly, the RDP Wrapper Library acts as a layer between the Service Control Manager and Terminal Services.
Pros: Survives most minor Windows updates without needing a re-patch.
Cons: Often flagged as a "HackTool" or "Trojan" by antivirus software like Windows Defender. Automated Scripting Termsrv.dll Patch Windows Server 2019 REPACK
Patching termsrv.dll allows Windows Server 2019 to bypass the default limitation of two simultaneous administrative RDP sessions. This method is often preferred over RDP Wrapper because it is less likely to be flagged by antivirus software. 🛠️ Preparation
Before starting, identify your exact Windows version to ensure you use the correct hex codes.
Check Version: Run Get-ComputerInfo | select WindowsProductName, WindowsVersion in PowerShell.
Backup: Copy C:\Windows\System32\termsrv.dll to a safe location (e.g., termsrv.dll.bak). 📝 Step-by-Step Patching Guide 1. Take Ownership of the File
By default, termsrv.dll is owned by TrustedInstaller. You must change this to the Administrators group. Open Command Prompt (Admin). Run: takeown /F c:\Windows\System32\termsrv.dll /A.
Run: icacls c:\Windows\System32\termsrv.dll /grant Administrators:F. 2. Stop Remote Desktop Services You cannot modify the file while the service is active. Run: net stop TermService. If prompted, stop dependent services like UmRdpService. 3. Edit the DLL (Hex Editor Method)
Open C:\Windows\System32\termsrv.dll in a hex editor like HxD or Tiny Hexer. For Windows Server 2019 (standard versions): Search for: 39 81 3C 06 00 00 0F 84 XX XX XX XX. Replace with: B8 00 01 00 00 89 81 38 06 00 00 90.
fabianosrc/TermsrvPatcher: Patch termsrv.dll so that ... - GitHub
Modifying core system files like termsrv.dll is not recommended for production environments due to several critical factors:
Security Vulnerabilities: Third-party "repacks" often come from unverified sources and may contain malware, backdoors, or keyloggers.
System Instability: Updates from Microsoft frequently replace this file. If a patched file is present during an update, it can cause the Remote Desktop service to crash or prevent the system from booting.
Legal Compliance: Bypassing license requirements is a violation of the Microsoft Software License Terms. For businesses, this can lead to failed audits and legal penalties. 🔍 Patch Functionality Review What it Attempts to Do
Unlock Sessions: Removes the hard-coded limit of two concurrent sessions. If you are reading this, you have likely
Enable Concurrent Users: Allows one user to log in while another is already active without forcing a logout.
Bypass RDS Roles: Attempts to provide terminal server functionality without installing the official Remote Desktop Services role. Technical Performance
User Experience: Often results in "Ghost Sessions" where users appear logged in but cannot interact with the desktop.
Maintenance: Requires re-patching every time Windows installs a monthly cumulative update, as the update will overwrite the modified termsrv.dll.
Compatibility: Many "repacks" found online are outdated and specifically tuned for older builds of Windows Server 2019, leading to instant service failure on modern builds. ✅ Recommended Professional Alternatives
Instead of using a high-risk patch, consider these legitimate methods for managing multiple sessions:
RDS CALs: The official way to enable multiple sessions is to install the Remote Desktop Services role and purchase the appropriate number of Client Access Licenses (CALs).
RDP Wrapper Library: If you must use a tool for testing or lab environments, the RDP Wrapper Library on GitHub is generally considered safer than a "repack." It works by loading the original DLL and applying changes in memory rather than overwriting the system file.
Remote Management Tools: For administrative tasks, use Windows Admin Center or PowerShell Remoting, which do not consume RDP session slots.
💡 Key Takeaway: While "Termsrv.dll" patches can technically enable multiple sessions, the risk of malware infection and system breakage far outweighs the cost of proper licensing for any professional or business setting. To give you a better recommendation, could you tell me:
Are you using this for a personal home lab or a business environment? How many concurrent users do you actually need to support?
Have you already experienced errors or crashes after attempting to use a patch?
termsrv.dll on Windows Server 2019 is a method used to bypass the default limit of two concurrent Remote Desktop Protocol (RDP) sessions without requiring the full installation of Remote Desktop Services (RDS) and associated Client Access Licenses (CALs). While often bundled in "repacks" or third-party scripts, this modification alters critical system binaries and carries significant risks. Purpose of the Patch Enable Concurrent Sessions If you want, I can:
: By default, Windows Server permits only two administrative RDP sessions. Patching the termsrv.dll
file removes this enforcement code to allow multiple users to connect simultaneously without disrupting existing sessions. Avoid RDS Role Installation
: It is used as a workaround to gain multi-user capabilities without setting up a full RDS infrastructure, which typically requires paid licensing. How the Patch is Applied
The process generally involves identifying specific byte patterns within the DLL and replacing them with a custom patch. Common tools and methods include: Patching Microsoft's RDP service yourself - Sam Decrock
I cannot produce a report for a "Termsrv.dll patch" or "REPACK" for Windows Server 2019. Here’s why:
Legitimate alternatives I can help you document instead:
If you received this file from an online source, I strongly recommend deleting it and running a full antivirus scan.
termsrv.dll is a common but unsupported method to bypass the default limit of two simultaneous Remote Desktop (RDP) sessions on Windows Server 2019. This modification allows for concurrent user sessions without requiring expensive Remote Desktop Services (RDS) Client Access Licenses (CALs). 🛠️ Patching Methods for Windows Server 2019
If you are looking to "repack" or manually patch the library, these are the primary community-driven methods: RDP Wrapper Library
: A popular "non-invasive" method that acts as a layer between the Service Control Manager and Terminal Services. It doesn't modify the termsrv.dll file itself, making it more resilient to Windows Updates. Find it on the official RDP Wrapper GitHub : You may need an updated rdpwrap.ini file for specific Windows Server 2019 builds. Manual Hex Editing
: For those who prefer a "repack" approach, you can manually modify the hex code within termsrv.dll using a tool like Tiny Hexer Search Pattern 39 81 3C 06 00 00 0F 84 Replacement B8 00 01 00 00 89 81 38 06 00 00 90 TermsrvPatcher (PowerShell) : Automation scripts like TermsrvPatcher
automate the process of taking ownership of the file, stopping the service, and applying the patch. ⚠️ Critical Risks and Warnings
fabianosrc/TermsrvPatcher: Patch termsrv.dll so that ... - GitHub
Windows Server 2019 receives monthly quality updates. A REPACK made for build 17763.1 will break after you install KB5025229 (or any later update). You’d have to re-apply the patch after each update – a maintenance nightmare.