Termsrv.dll Patch Windows Server 2016

to ensure you use the correct patch. Detail the steps to undo the patch if it causes issues.

Always keep a copy of the original file in case the patch fails or Windows Updates break the patched version.

In real-world scenarios—whether you’re managing a small business server, coordinating a development team, or running a multi-user application environment—this two-session cap quickly becomes a severe operational bottleneck. The termsrv.dll patch has emerged as one of the most popular (and controversial) solutions to this problem. This comprehensive guide explores everything you need to know about patching termsrv.dll on Windows Server 2016, including how it works, step-by-step implementation, security risks, legal considerations, and alternatives.

Note: If your build is fully updated, you may need to search for variations starting with 39 81 or use an open-source automated patching tool like RDPWrap, though tools must match your exact OS build. Step 4: Replace the Original File

Open regedit and check: HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server fDenyTSConnections should be 0 . (If AllowMultipleTSSessions exists, set to 1 .) termsrv.dll patch windows server 2016

The patch targets specific byte sequences within the termsrv.dll file (located in C:\Windows\System32 ) to bypass the hard-coded session limit. : %SystemRoot%\System32\termsrv.dll .

Remote Desktop must be turned on in System Properties. Step-by-Step Procedure

While in Safe Mode or with testsigning on:

By default, the NT SERVICE\TrustedInstaller account owns critical system files. You must transfer ownership to the local Administrators group to modify it. Open File Explorer and navigate to C:\Windows\System32 . Locate termsrv.dll , right-click it, and select . Go to the Security tab and click Advanced . Next to the Owner field, click Change . to ensure you use the correct patch

| Drawback | Description | |----------|-------------| | | Using the patch for any purpose beyond administrative access violates Microsoft licensing terms | | Security Exposure | Systems using patches often delay security updates, leaving known vulnerabilities unpatched | | Operational Instability | Windows updates frequently break patches; restoring functionality may require manual intervention during outages | | Missing Official Support | Microsoft will refuse support for any system with modified termsrv.dll |

copy C:\Windows\System32\termsrv.dll C:\Windows\System32\termsrv_backup.dll

To maintain system integrity, you should return ownership to TrustedInstaller .

Reddit users have similarly reported RDP failures after updates like requiring the update to be uninstalled to restore functionality. This creates an impossible “break-fix” cycle where administrators must choose between security updates and functional multi-user RDP access. Note: If your build is fully updated, you

Windows Server 2016 receives monthly security updates [Microsoft 2026]. Keep your system updated to protect against vulnerabilities.

If issues arise after patching termsrv.dll , consider the following steps:

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.