From different PCs or using mstsc /admin variations, try opening 3+ concurrent RDP connections.
Do not edit the file in System32 directly. Copy it to your Desktop or C:\temp: termsrv.dll patch windows server 2016
copy C:\Windows\System32\termsrv.dll C:\temp\
The termsrv.dll patch for Windows Server 2016 offers a tempting way to unlock unlimited concurrent RDP sessions without licensing costs. For homelabs, testing, and non-critical internal tools, it remains a popular workaround. However, production environments should never rely on this hack. From different PCs or using mstsc /admin variations,
By following the step-by-step manual patching guide above—backing up files, using the correct hex pattern, and understanding the risks—you can safely remove the two-session limit. Just remember: every Windows Update may break the patch, and Microsoft’s licensing team will not forgive violations. Do not edit the file in System32 directly
If you truly need multi-user RDP, budget for RDS CALs. But for the tinkerer and the budget-conscious lab admin, the termsrv.dll patch lives on as a clever, if unsanctioned, solution.
By default, termsrv.dll is owned by TrustedInstaller and cannot be modified.
takeown /f C:\Windows\System32\termsrv.dll
icacls C:\Windows\System32\termsrv.dll /grant "%USERNAME%:F"
termsrv.dll.backup) immediately.