In Windows client operating systems, only one simultaneous incoming RDP connection is supported. That’s means that only one user can simultaneously connect to a Windows computer using RDP. When you trying to start the second RDP session, a message “Another user is signed in. If you continue they’ll be disconnected. Do you want to sign anyway?” appears. Sometimes, it would be useful if multiple users could work simultaneously in their own sessions. Basically, that is not possible without Terminal Services, but if you are ready to patch Remote Desktop, you can provide two simultaneous connection.
Download modified termsrv.dll and replace with existing. File is located in %SystemRoot%\System32\termsrv.dll.
! ! ! Please save a copy of current termsrv.dll, if you need to roll back changes ! ! !
Change the values of the following keys in HKLM\System\CurrentControlSet\Control\Terminal Server\:
fDenyTSConnections (DWORD) – From 1 to 0
fSingleSessionPerUser (DWORD) – From 1 to 0
You can do that also with command prompt
REG ADD “HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server” /v fDenyTSConnections /t REG_DWORD /d 0 /f
REG ADD “HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server” /v fSingleSessionPerUser /t REG_DWORD /d 0 /f
Replace original file with downloaded modified termsrv.dll. Because owner of termsrv.dll is TrustedInstaller, by default you can to anything with this file. You need to give full access to user who will replace original file. Sometimes that is not possible, and you need to take file ownership.
Before replacing original file, you need to stop Remote Desktop Services, and start again after replacing file.
Now, more than one simultaneous session will be allowed to computer.