High Quality Content by WIKIPEDIA articles! Client/Server Runtime Subsystem, or csrss.exe, is a component of the Microsoft Windows NT operating system that provides the user mode side of the Win32 subsystem and is included in Windows 2000, Windows XP, Windows 2003, Windows Vista, Windows Server 2008 and Windows 7. Because most of the Win32 subsystem operations have been moved to kernel mode drivers, in Windows NT 4 and later CSRSS is mainly responsible for Win32 console handling and GUI shutdown. It is critical to system operation; therefore, terminating this process will result in system failure. Under normal circumstances, CSRSS cannot be terminated with the taskkill command or with Windows Task Manager, though it is possible in Vista if the Task Manager is run in Administrator mode. On Windows 7 and Windows 8 Developer Preview, Task Manager will inform the user that terminating the process will result in system failure, and prompt if they want to continue.