Utilizing Multiple Monitors in a Remote Desktop Session.

Multiple monitor support for Remote Desktop Services allows users to extend a Remote Desktop connection across all monitors on the client computer, regardless of the monitor configuration. This feature enables users to utilize all connected monitors in a Remote Desktop session, providing additional workspace and a seamless experience, much improved over “Span mode.” This capability is available in the Windows 7/Windows Server 2008 R2 release and works for connections to either a physical or virtual machine or a Remote Desktop Session Host.

How to Enable Remote Desktop Multi-Monitor Feature: To use the multi-monitor feature, follow these steps:

1. Connect with Remote Desktop Client 7.0 (mstsc.exe), initially available in Windows 7/Windows Server 2008 R2.
2. Enable multi-monitor mode using one of these methods:
   • Select “Use all monitors for the remote session” in the mstsc.exe window.
   • Use the “/multimon” switch in the mstsc.exe command line.
   • Add “Use Multimon:i:1” to the RDP file.
3. Connect to a machine running Windows 7 or Windows Server 2008 R2.

How does it differ from “Span” mode? Span mode, introduced in Vista, spans the remote desktop across all client monitors but treats it as a single-monitor session. In contrast, multi-monitor support treats each client monitor as distinct in the remote session, offering greater flexibility. Span mode requires the primary monitor to be on the left and the monitors to form a rectangle with uniform vertical resolution. It also limits the total resolution to 4096×2048. Multi-monitor mode has no such restrictions and allows monitors to be arranged in any order and resolution.

In span mode, maximizing a window spans it across all monitors, while in multi-monitor mode, the window maximizes only within its respective monitor. Additionally, multi-monitor mode accurately reflects the number of monitors to applications, unlike span mode, which only reports a single monitor.

Multi-Monitor Configuration Settings: Multi-monitor functionality can be customized with settings that limit the number of monitors or their resolutions. By default, RDP supports up to 16 monitors, but this can be restricted using:

• The “Limit maximum number of monitors per session” option in the Remote Desktop Configuration Tool (tsconfig.msc).
• Group policy settings.
• The MaxMonitors property in the Win32_TSClientSetting WMI class.

Similarly, the maximum resolution can be restricted via group policy or by setting the MaxXResolution and MaxYResolution properties in the Win32_TSClientSetting WMI class.

Note: These settings apply only to multi-monitor connections, not single-monitor connections.