The termsrv.dll patch for Windows Server 2016 remains a powerful, time-tested tool for breaking the two‑session RDP shackles in non‑production environments. It is a testament to the community's desire to bypass artificial restrictions for legitimate lab, testing, or legacy use cases.
However, the risks—security vulnerability, update instability, and licensing violations—make it unsuitable for any business‑critical production environment. For those scenarios, invest in proper RDS CALs or alternative remote access solutions.
If you choose to patch, always:
Otherwise, RDP Wrapper offers a safer, more maintainable approach that doesn't require disabling code integrity checks.
Remember: With great power comes great responsibility—and the risk of a non-compliant, unsupported server. Patch wisely.
Disclaimer: This article is for educational purposes only. The author and publisher are not responsible for any damage, data loss, or licensing violations resulting from the use of this information. Always adhere to Microsoft’s licensing terms and software agreements. termsrv.dll patch windows server 2016
Patching termsrv.dll on Windows Server 2016 is a technique used to bypass the default limitation that allows only two concurrent Remote Desktop Protocol (RDP) sessions. While Windows Server naturally supports more sessions through the Remote Desktop Services (RDS) role, it requires valid Client Access Licenses (CALs); patching is often an unofficial workaround to avoid these licensing requirements or to enable concurrent sessions on non-server editions. Technical Mechanism of the Patch
The patch targets specific binary instructions within the termsrv.dll file (located in C:\Windows\System32) that check for session limits.
Byte Modification: Typically, a hex editor or script is used to find a specific pattern of bytes—such as 39 81 3C 06 00 00—and replace them with a sequence like B8 00 01 00 00 89 81 38 06 00 00 90.
Logical Bypass: This modification effectively forces the internal check for "maximum allowed sessions" to always return a value that permits additional users, rather than triggering a "disconnect existing user" prompt.
Service Interaction: For the patch to take effect, the Remote Desktop Service (TermService) must be stopped, and the administrator must take ownership of the system file from TrustedInstaller to gain write permissions. Popular Tools and Methods Several community-developed tools automate this process: Patching Microsoft's RDP service yourself - Sam Decrock The termsrv
The "termsrv.dll patch windows server 2016" refers to a specific patch or update related to the Remote Desktop Services (RDS) component in Windows Server 2016, focusing on the termsrv.dll file. This DLL (Dynamic Link Library) is crucial for the functioning of Remote Desktop Services, which allow users to remotely access and interact with a Windows Server environment.
Do not edit the file in System32 directly. Copy it to your Desktop or C:\temp:
copy C:\Windows\System32\termsrv.dll C:\temp\
If you need more than 2 concurrent RDP sessions on Windows Server 2016, consider these legitimate alternatives:
termsrv.dll (Terminal Services DLL) is a critical system file located in C:\Windows\System32\. It manages RDP session handling, licensing validation, and concurrent connection logic. Every time a user connects via RDP, termsrv.dll checks:
By default, Windows Server 2016 allows only two concurrent administrative sessions (for remote management) without RDS roles installed. Any third user receives the infamous error: Otherwise, RDP Wrapper offers a safer, more maintainable
"The remote session was disconnected because there are no Remote Desktop License Servers available."
The termsrv.dll patch modifies specific byte patterns inside the DLL to bypass this license check.
If you need concurrent RDP sessions legally and reliably, consider:
Disclaimer: Modifying system DLLs carries inherent risks. Always create a full backup or system restore point before proceeding. This guide is for educational purposes and assumes you have the necessary administrative rights. If you are using Windows Server in a production environment, it is highly recommended to purchase legitimate Remote Desktop Services (RDS) CALs instead of patching system files.
You cannot modify termsrv.dll because Windows protects it. You must claim ownership.
Note: Builds with newer cumulative updates may need different patterns. Search online for "termsrv.dll hex pattern for Server 2016 build XXXXX" where XXXXX is your UBR.