Termsrv.dll Patch Windows Server 2016 (RECENT · SOLUTION)
Patching termsrv.dll on Windows Server 2016 is crucial for maintaining server security and RDS functionality. By understanding the process and following best practices, administrators can ensure their servers remain up-to-date and resilient against potential threats. Always proceed with caution when applying updates and take necessary precautions to protect your server environment.
Patching termsrv.dll on Windows Server 2016 is typically done to enable multiple concurrent Remote Desktop (RDP) sessions without purchasing Remote Desktop Services (RDS) Client Access Licenses (CALs).
Warning: This process modifies system files and may violate Microsoft's Licensing Terms. It is highly recommended to perform a full system backup or create a system restore point before proceeding. Manual Patching Steps
If you choose to perform this manually, you will need to take ownership of the file and replace specific hex strings. Stop Remote Desktop Services: Open Services.msc.
Locate Remote Desktop Services, right-click it, and select Stop. Take Ownership of termsrv.dll: Navigate to C:\Windows\System32\.
Right-click termsrv.dll -> Properties -> Security -> Advanced. Change the Owner to your administrator account. termsrv.dll patch windows server 2016
Close and reopen the properties to grant your account Full Control permissions. Backup the Original File: Copy termsrv.dll and rename the copy to termsrv.dll.bak. Edit the File with a Hex Editor: Open termsrv.dll in a tool like HxD Hex Editor.
Search and Replace: You must find specific hex strings based on your exact Windows build version. For many Windows Server 2016 versions, the common target is changing: 39 81 3C 06 00 00 0F 84 XX XX XX XX
B8 00 01 00 00 89 81 38 06 00 00 90 (Note: The exact string varies by build; check community repositories for your specific build number). Restart Services: Save the file.
Go back to Services.msc and Start the Remote Desktop Services. Automated Alternatives
Because manual hex editing is prone to error and gets overwritten by Windows Updates, many users prefer automated scripts: Patching termsrv
TermsrvPatcher (GitHub): This TermsrvPatcher repository provides a PowerShell script to automate the process and includes a Scheduled Task to re-apply the patch automatically after Windows Updates.
RDPWrap (RDP Wrapper Library): While often flagged by antivirus as a "hacktool," this is a popular open-source project that acts as a layer between the Service Control Manager and Terminal Services, meaning it doesn't modify the original termsrv.dll file directly. Maintenance Considerations
Windows Updates: Major updates often replace termsrv.dll, which will break your patch. You will likely need to re-apply the patch or update your script after every "Patch Tuesday".
Registry Verification: Ensure that HKLM\System\CurrentControlSet\Control\Terminal Server\fSingleSessionPerUser is set to 0 if you want a single user to be able to open multiple sessions.
Do you need to find the specific hex string for your particular build number (e.g., Build 14393)? For IT administrators, developers, and tech enthusiasts who
fabianosrc/TermsrvPatcher: Patch termsrv.dll so that multiple ... - GitHub
Windows protects this file strictly. You must take ownership to edit it.
For IT administrators, developers, and tech enthusiasts who manage Windows Server 2016 machines, one limitation stands out as a persistent thorn in the side: the stringent two concurrent Remote Desktop Protocol (RDP) session limit.
Windows Server 2016, by default, allows only two simultaneous administrative remote connections. This is by design—Microsoft intends this for light server management, not for multi-user access scenarios. However, in lab environments, development servers, legacy application hosting, or even small businesses on a budget, the need for more than two concurrent users arises frequently.
Enter the termsrv.dll patch—a community-driven, unofficial modification that has been a rite of passage for Windows Server administrators for generations (from Windows 2000 to Windows Server 2019). This article provides an exhaustive, technical, and practical guide to applying the termsrv.dll patch on Windows Server 2016, including what it is, how it works, step-by-step instructions, risks, alternatives, and post-patch management.