What /admin key for mstsc.exe actually does

/admin key is usually used for RDS server administration. When you use mstsc.exe /admin to connect to the Windows Server with RDS role installed it does the following for the initiated connection:\n\n- Disables RDS client access licensing\n\n- Disables timezone redirection\n\n- Disables RD Connection Broker redirection\n\n- Disables RD Easy Print\n\n- Disables PnP device redirection for this connection only\n\n- Changes the remote session theme to Windows Classic View (it it’s available) for this connection only