To enable multiple concurrent user sessions without purchasing Remote Desktop Services Client Access Licenses (RDS CALs), administrators often patch the termsrv.dll file. This guide explains how the patch works, how to implement it, and the associated risks. ⚠️ Important Warning and Legal Disclaimer
Purchase and install the appropriate number of via the Remote Desktop Licensing Manager.
For production environments, it is strongly recommended to use proper RDS CALs to ensure compliance and supportability. If you'd like, I can:
In the administrative Command Prompt, stop the Remote Desktop service ( TermService ): net stop TermService /y Use code with caution.
(Note: The exact bytes may vary slightly depending on the specific Windows Server 2016 cumulative update installed. Always check your specific build number before editing.) Using Automated Scripts termsrv.dll patch windows server 2016
# Download the latest release from GitHub # Run install.bat as Administrator # The installer downloads the latest rdpwrap.ini configuration automatically install.bat
What of Windows Server 2016 are you currently running?
Running System File Checker ( sfc /scannow ) or DISM deployment cleanup tools will detect that termsrv.dll has been modified or corrupted. Windows will automatically replace your patched file with a clean version from the component store ( WinSxS ). If you must run these repair utilities, remember to re-apply the patch immediately afterward. Final Thoughts
Before modifying the file, you must take ownership from "TrustedInstaller." powershell For production environments, it is strongly recommended to
Copy the file and paste it into a secure backup directory (e.g., C:\Backup\termsrv.dll.bak ). Step 2: Take Ownership of Termsrv.dll
For Windows Server 2016 (Build 14393), typical hex changes include: Find: 39 81 3C 06 00 00 0F 84 D3 DE 02 00 Replace: B8 00 01 00 00 89 81 38 06 00 00 90 .
For production environments, purchase legitimate RDS CALs. Step 1: Stop the Remote Desktop Service
I can provide the exact hex string or configuration file block needed for your specific version. Share public link Always check your specific build number before editing
Using a patched termsrv.dll exposes you to several major risks:
You cannot modify the file while the Remote Desktop service is actively using it.
RDP Wrapper offers the advantage that it does not write changes to termsrv.dll on disk, making it easier to revert simply by running uninstall.bat .