Modifying system files requires elevated privileges and careful execution. Below is the manual process for patching termsrv.dll on Windows Server 2022. Step 1: Terminate the Remote Desktop Service
The RDP Wrapper Library is a popular open-source alternative.
If the service throws an error after starting, your hex modifications are incorrect. Restore the backup using copy /y C:\Windows\System32\termsrv.dll.bak C:\Windows\System32\termsrv.dll and restart the service.
copy C:\Windows\System32\termsrv.dll C:\Windows\System32\termsrv.dll.bak Use code with caution. Step 4: Patch the File via Hex Editor termsrv.dll patch windows server 2022
Navigate to C:\Windows\System32\termsrv.dll .
39 81 3C 06 00 00 0F 84
Warning: Because RDP Wrapper relies on static configuration (.ini) files, it frequently breaks when Windows Update changes the internal structure of termsrv.dll. Group Policy Modifications If the service throws an error after starting,
You must log in as a local administrator. Backup: Create a copy of the original termsrv.dll file.
Confirm the prompt by typing Y if it asks to stop dependent services like BlueStripe or UmRdpService. Step 3: Edit the Hex Values
Windows Update routinely updates system files to patch security vulnerabilities. Whenever Microsoft releases a cumulative update affecting Remote Desktop Services, the patched termsrv.dll will be overwritten by a fresh, unpatched version from Microsoft. This resets your concurrent session limit back to two, requiring you to repeat the patching process frequently. The Official Alternative: Configuring RDS Role Step 4: Patch the File via Hex Editor
Several community tools exist (use with caution):
Safer, supported alternatives
Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass .\TermsrvPatcher.ps1 Use code with caution. Copied to clipboard
The RDP Wrapper Library functions as a layer between the Service Control Manager and the Terminal Services. Instead of modifying the actual termsrv.dll file on your disk, it loads the file into memory and applies the modifications dynamically.