net start TermService
net start UmRdpService
Or simply reboot.
You cannot modify the file while it is in use by the system.
To maintain system integrity, you should return ownership to TrustedInstaller.
The classic method involves replacing the original termsrv.dll with a hex-edited version or using an automated patcher (e.g., "RDP Wrapper" or "Universal Termsrv.dll Patch"). Below is the conceptual process for Windows Server 2016.
Before you start:
Manual Hex-Edit Approach (Conceptual)
Backup the Original:
copy C:\Windows\System32\termsrv.dll C:\termsrv_backup.dll
Hex-Edit the DLL (Version-specific):
Replace the DLL & Restart:
copy /y modified_termsrv.dll C:\Windows\System32\termsrv.dll
net start TermService
Easier (But Still Unsafe) Method – Use a Tool
Tools like RDP Wrapper Library attempt to dynamically configure RDP limits without permanently patching the DLL. They often fail after Windows updates.
The patch does not remove licensing entirely—it alters the conditional logic inside the DLL. Specifically, it tricks the server into believing that:
Technically, the patch replaces a JE (Jump if Equal) or JNE (Jump if Not Equal) assembly instruction with a JMP (unconditional jump) or NOP (No Operation) at a specific memory offset. This causes the license-check routine to always return a "success" value. termsrv.dll patch windows server 2016
For Windows Server 2016 (builds 1607, 1709, 1803, 1809, 1903, 1909, 2004, 20H2), the patch targets termsrv.dll version 10.0.14393.x and higher.
Windows Server 2016 remains a workhorse in data centers and small-to-medium businesses (SMBs) worldwide. It is stable, secure, and feature-rich. However, one long-standing limitation frustrates many administrators: the default restriction of two concurrent Remote Desktop Protocol (RDP) sessions for administrative purposes.
While Windows Server 2016 officially supports Remote Desktop Services (RDS) to allow multiple users, this requires purchasing RDS Client Access Licenses (CALs). For non-production environments, labs, legacy application hosting, or small teams, the cost and overhead of RDS CALs can be prohibitive.
Enter the termsrv.dll patch—a community-driven modification that lifts the concurrent session limit by patching the core Terminal Services DLL file. This article provides an exhaustive, step-by-step guide to applying the termsrv.dll patch on Windows Server 2016, including risks, alternatives, and best practices. net start TermService net start UmRdpService
Because manual hex editing is tedious, the community has created automated patchers: