If you have multiple monitors, you may want to have the Remote Desktop Session for a particular computer always appear on the same monitor. Unfortunately, the Remote Desktop Connection user interface does not expose a setting like "Display Session on Monitor X." There is a way to do this, but it is neither easily discoverable nor intuitive. This article shows you how to configure a saved remote desktop connection so that sessions to a particular computer always appear on the monitor that you choose.

The Default.rdp file

By default, remote desktop saves the settings for a remote desktop session in a file called Default.rdp. In Windows 7, Default.rdp saves by default to the %homedrive%%homepath\Documents directory.
You can edit this file by right clicking it and selecting Edit. The Remote Desktop Connection dialog that appears has a Display tab. This tab allows you to choose the resolution for the session, and even has a checkbox called Use all my monitors for the remote session, but there is no option to choose a particular monitor for a remote session if you want to use just one monitor.

Save a Separate .rdp File for Each Remote Computer

The first step is to save and keep a separate remote desktop configuration .rdp file for each computer that you want to access remotely.
To save a separate .rdp file:

 1. Open the Remote Desktop Connection dialog. In Windows 7, one of the easiest ways to do this is to click Start, type "remote" in the Search programs and files box, and click the Remote Desktop Connection icon that appears in the search results. 

2. In the Remote Desktop Connection dialog, enter the name of the computer to which you will connect.
3. Click the Options button in the lower left corner. This will reveal a Save As button.
4. Save the file with a name that you will easily recognize, preferably with the name of the computer itself.
  In Windows Explorer, use Notepad or other text editor to open the.rdp file that you saved. Right-click the file, and instead of choosing Edit, choose Open with, and select Notepad. If necessary, navigate to %windir%\System32 directory, and select Notepad.exe.

Analyzing the .rdp File

The .rdp file contents will look like this:
screen mode id:i:2
use multimon:i:0
session bpp:i:32
Look for the keyword winposstr. The most important parameters are the numbers after winposstr. Ignore the initial ":s:0,1," and focus on the last four comma-delimited numbers.
The last four numbers express, in pixels, the position of the left, top, right, and bottom edges of the remote session window.
The numbers actually refer to the window position when the window is restored, but the pixel position of the left edge of the window is important because it also determines the monitor that the remote session will use when the window is maximized.

Calculating the Values for winposstr

The numbers that you will use depend on how many monitors you have, the screen resolutions of each, and which monitor you have selected to be your primary monitor.

Left edge position determines the monitor

The first of the last four numbers, which is the most important, indicates the position of the left edge of the window. If your primary monitor is in the center and you have monitors to the left and right, you will use a negative number for the monitors to the left, and a positive number for the monitors to the right.
For example, if you have two monitors to the left that each have a resolution of 1680 x 1050, use -1680 to place the session window on the monitor to the immediate left, and double that (-3360) to place the window on the leftmost monitor.
If your primary monitor has a resolution of 1200 x 1920, use 1200 to place the window on the monitor on the immediate right. This works because that pixel position is where the primary monitor leaves off (and the monitor on the right begins).
If you have two monitors on the right with a resolution of 1680 x 1050, and want to place the window on the rightmost monitor, simply add 1200 to 1680 to get 2880.

Top and Bottom Edges

The other numbers only really come into play when the window is restored (not maximized) and can be adjusted to taste.
The second number (third from the end) indicates the topmost edge of the window, so you can leave this number at 0 unless you have special requirements. The fourth (last) number is the vertical resolution (=bottom) of the window. You can leave this at the maximum vertical resolution of the monitor, as in the examples above.  
winposstr:s:0,1,1200,0, 2880,1050

Right Edge

The right edge of the window is expressed by the next to the last number. Unless you prefer otherwise, this can be set to the same size as the maximized window. Following the monitor resolution examples above, here are the calculations:
Monitor Right Edge Calculation   Winposstr Value
Leftmost -3360 + 1680 = -1680 winposstr:s:0,1,-3360,0,-1680,1050
Immediate left -1680 + 1680 = 0 winposstr:s:0,1,-1680,0,0,1050
Immediate right 1200 + 1680 = 2880 winposstr:s:0,1,1200,0,2880,1050
Rightmost 1200 + 1680 + 1680 = 4560 winposstr:s:0,1,2880,0,4560,1050



Fortunately, RDP remembers the number for the left edge of the restored window and positions the maximized window based on that. Because of this, after you set the "restored window" winposstr values as in the examples above, you can use the .rdp file to open a session in a maximized state, and the window will appear in the position (and therefore on the monitor) that you have set.

Configuring the Remote Session to Always Open Maximized

To have the remote session always open in a maximized window, you can either use the Remote Desktop Connection dialog, or edit the .rdp file directly. To use the Remote Desktop Connection dialog, click the Display tab and set the Display configuration to Full Screen. To edit the the .rdp file directly, set the screen mode id value to 2, as in the following example.
screen mode id:i:2
If for some reason the remote desktop session does not fill your screen when maximized, you can manually set the maximum screen size by manually modifying the desktopwidth and desktopheight parameters in the .rdp file. For example, this will set the resolution to 1680x1050:

Using the Edited.rdp File

To launch a remote session based on your edited .rdp file, you can double click it in Windows Explorer or use the Remote Desktop Connection dialog to browse to the file and open it (from the dialog, click Options, then Open), but you may find it more convenient to just create a shortcut to the .rdp file and place the shortcut on your desktop where you can access it immediately.