Because Windows Server 2016 updates can change the exact build number, the hex pattern might vary slightly depending on your update level. Copy C:\Windows\System32\termsrv.dll to your Desktop. Open the desktop copy in your Hex Editor.

: The byte replacement corrupted the DLL file structure due to a build version mismatch.

Windows updates ( KB patches) often replace termsrv.dll , reversing the patch and requiring it to be reapplied.

and replacing it with a sequence that ignores the session check. RDP Wrapper Library : An open-source tool, RDP Wrapper

Before proceeding, understand the consequences:

Patching termsrv.dll circumvents Microsoft’s licensing requirements for multi‑user RDP access. While this is technically feasible, it violates the End User License Agreement (EULA) for Windows Server 2016. Organisations should evaluate their compliance posture before deploying the patch in production environments. For any commercial or critical deployment, purchasing the appropriate RDS CALs is the recommended, legally sound path.

Note: Patterns vary by build. For Windows Server 2016 (Build 14393), common patterns involve searching for 39 81 3C 06 00 00 and replacing it with specific overrides.