1. Download the zipped patch file win81rdp.zip that includes both original and patched version of termsrv.dll file for both 32-bit and 64-bit editions.
2. Stop Remote Desktop Services service from Services MMC console.
3. Replace the ownership of termsrv.dll file in c:\windows\system32 folder with an user account that has local admin privilege. And give that user a full control permission on termsrv.dll file.
4. Make a copy of original termsrv.dll file and overwrite it with one from zipped patch file downloaded on step 1.
5. Restart Remote Desktop Services or reboot your computer.