Run multiple instances with one click in Visual Studio

I wonder if I can run multiple instances (right now two instances) of my application in debug mode by doing a simple click or set a key for that...

Not many people seem to know this, but this is perfectly possible, though I admit it's not very obvious. Here's what you do:

• suppose your current project is A, and it's output is c:\bin\my.exe
• add an empty project to the solution for A, call it 'Dummy'
• under Dummy's Project Properties->Debugging set the Command to point c:\bin\my.exe
• under Solution Properties->Configuration Manager, uncheck all builds of the Dummy project so VS won't try to build it (building an empty project fails)
• under Solution Properties->Startup Project, select Multiple Startup Projects and set the Action for both A and Dummy to Start
• now hit F5 and your exe will be launched twice, each under a seperate debugging instance. (as you will be able to see in the Debug->View->Processes window)

You can use "Multiple Startup Projects" feature, but avoid creating dummy projects by hand: just add your debuggee executable into the solution directly:

• Solution > Add existing project > Path to .exe

If you neeed several instances, Visual Studio won't allow you to add the same executable twice, but adding a symlink to it with another name works as expected.

MSDN: How to: Debug an Executable Not Part of a Visual Studio Solution

Is Visual Studio 2013 this is even easier!

Project-> Properties -> Debug -> check "Start external program" and click the ... button, navigate to your .exe of the other program.

Then Make sure in your Solution -> Properties -> MultipleStartup Projects that it's checked.