By default, Windows Server 2012 R2 limits concurrent Remote Desktop Protocol (RDP) connections. If you attempt to connect multiple users simultaneously under certain configurations or licensing states, the system will prompt you to disconnect an existing user.
This error occurs when the session arbitration logic fails. Ensure you have disabled the single-session restriction in gpedit.msc as outlined in the Group Policy section above. SFC /Scannow Reverts the Patch
Back on the Security tab, click . Select the Administrators group and check the box for Full Control . Click Apply and OK . Step 3: Backup the Original File universal termsrv.dll patch windows server 2012 r2
The tool (often UniversalTermsrvPatch-x64.exe for Server 2012 R2) identifies the version of your termsrv.dll .
This modifies a system file. Create a backup and a System Restore point first. By default, Windows Server 2012 R2 limits concurrent
If the hex string is modified incorrectly, or if a Windows Update partially changes the file structure, the Remote Desktop service will fail to start entirely. This can lock administrators out of the server completely, requiring physical access or an IPMI/KVM console to fix. 4. Severe Security Vulnerabilities
If you are using a hex editor (such as HxD), you need to search for a specific byte pattern unique to the Windows Server 2012 R2 version of termsrv.dll and replace it to remove the session check. Look for: 39 81 3C 06 00 00 0F 84 Replace with: B8 00 01 00 00 90 89 44 Ensure you have disabled the single-session restriction in
System files are protected by TrustedInstaller . You must manually take ownership of the file to modify it.
Always create a copy of your original termsrv.dll . If the system becomes unstable or an update breaks the file, you will need the original to restore functionality.