How to set multiple startup projects in Visual Studio

This feature is particularly handy when you have several projects in a solution that you want to launch simultaneously, whether with or without debugging. Previously, you had to designate one project as the startup project, start it, and then repeat the process for each project, which was quite tedious!

How to set multiple startup projects?

1. Right-click on the solution and select Properties, or use the shortcut “Set Startup Projects…”.
2. Navigate to the Startup Project section.
3. Choose Multiple startup projects.
4. For each project you wish to start, set it to Start.
5. Click Apply.

Visual Studio Solution Property Pages showing multiple startup projects set to Start.

For optimal results, I recommend setting all target projects to Start. This allows you the flexibility to launch them with or without the debugger.

Note: To revert to a single startup project, simply right-click on your preferred project and select Set as Startup Project there’s no need to go through the solution property pages for that.

If all projects are set to Start without debugging, you may encounter an error message: "Unable to start debugging. The startup project cannot be launched." Sometimes, it may fail silently, which can be frustrating. In contrast, setting all projects to Start allows you to initiate them with or without the debugger as needed.

Lastly, be cautious that the multiple startup projects list includes all projects, even those that can’t function as startup projects. Ensure those are set to None (the default setting).