Because Microsoft updates termsrv.dll during cumulative monthly updates, the exact hex patterns can shift depending on your specific Windows Server 2019 build version. Below is the universal methodology to apply the patch manually or via automated scripting. Step 1: Terminate the Remote Desktop Service
The restriction on concurrent RDP sessions is not a hardware capability limit; it is a software-enforced restriction coded directly into the Remote Desktop Services library file, located at %SystemRoot%\System32\termsrv.dll .
To apply the KB5011493 patch to your Windows Server 2019 system, follow these steps:
The termsrv.dll file is the core component of Remote Desktop Services on Windows. It is located in C:\Windows\System32\ . This DLL handles RDP connections, user authentication, and session management.
For Windows Server 2019, this often involves searching for a specific hex string (like 39 81 3C 06 00 00 0F 84 ) and changing the jump instruction ( : No extra software running. windows server 2019 termsrvdll patch patched
automatically handle taking ownership, stopping services, patching, and restarting the service. Download a trusted TermsrvPatcher.ps1 (e.g., from fabianosrc/TermsrvPatcher on GitHub Open PowerShell as Administrator. Navigate to the folder and run: .\TermsrvPatcher.ps1 Method 2: Manual Patching (Hex Editor) If you prefer to patch manually to ensure safety: Stop Remote Desktop Service: Open CMD as Admin and run: net stop TermService Take Ownership: Take ownership of %SystemRoot%\System32\termsrv.dll and grant Administrators Full Control. termsrv.dll termsrv.dll.bak Use a hex editor to change the bytes. 39 81 3C 06 00 00 0F 84 E3 2B 01 00 (Values vary by build). B8 00 01 00 00 89 81 38 06 00 00 90 Restart Service: net start TermService How to Verify Group Policy Editor gpedit.msc Computer Configuration Administrative Templates Windows Components Remote Desktop Services Remote Desktop Session Host Connections
With the release of in late 2020 and throughout 2021, Microsoft introduced a significant change: digital signature enforcement on termsrv.dll .
: Replacing system DLLs with files downloaded from untrusted sources is a major security risk. Always use a reputable script or perform the hex edit yourself. 🚀 How to Verify
Enabling Multiple RDP Sessions on Windows Server 2019 Windows Server 2019 is designed for multi-user environments, but by default, it restricts Remote Desktop (RDP) to only two concurrent sessions for administrative purposes. For businesses needing to support a larger workforce, you often face a choice: pay for costly Remote Desktop Services (RDS) Client Access Licenses (CALs) or find a technical workaround. One common "underground" method involves patching the termsrv.dll Because Microsoft updates termsrv
copy C:\Windows\System32\termsrv.dll C:\Windows\System32\termsrv.dll.bak Use code with caution. Step 4: Edit the Hexadecimal Code
By default, Windows Server 2019 allows for administrative purposes without installing the Remote Desktop Session Host (RDSH) role. This is intended for server management, not for use as a terminal server. Many small businesses and developers have long sought ways to exceed this limit without purchasing RDS Client Access Licenses (CALs).
The termsrv.dll patch for Windows Server 2019 is a community-developed modification used to bypass Microsoft's default restriction on concurrent Remote Desktop Protocol (RDP) sessions. While Windows Server 2019 natively supports multiple sessions, it requires specific roles and licenses that some administrators seek to avoid through this unauthorized patch. Purpose and Functionality
It is important to note that patching termsrv.dll to bypass session limits generally violates the Microsoft Software License Terms. For production environments, the only supported method for increasing RDP sessions is purchasing and installing . Troubleshooting a Failed Patch If you find that RDP no longer works after a patch: To apply the KB5011493 patch to your Windows
: Using pre-patched files from untrusted internet sources is a high-risk activity. These files can be bundled with malware or backdoors, compromising the entire server infrastructure. Legal and Compliance Factors
In updates such as KB5001342 (May 2021) and subsequent servicing stack updates, Microsoft implemented:
is against Microsoft's End User License Agreement (EULA). It can make your system unstable, break Remote Desktop functionality entirely during Windows Updates, and poses security risks. Always create a backup before proceeding. MITRE ATT&CK® Pre-Requisites Version Check: Identify your exact Windows Server 2019 build (e.g., 10.0.17763.xxx ) by running Administrator Rights: You must have administrative access. Method 1: Using automated Patcher (Recommended) Tools like TermsrvPatcher