Hello! I'm back again.

When I build the entire solution, I get these 12 errors from the Arduino project. (Link to Pastebin).

Please note that the build succeeds nonetheless, and the errors don't appear when only building a specific project instead of the entire solution.

Yes it does.

After adding a third project to the solution the problem doesn't manifest itself anymore.

It used to happen with either project as the Startup project, and the other projects used to build ok.

Hi,

This error shows when an arduino project is in the solution but is not the "Startup project". When you click Build>Solution the Visual Studio engine is allowed to attempt to build the arduino project as a windows project.

This is useful for advanced user who cross-compile with other tools.

If you don't want this facility then click "Build>Configuration Manager" and deselect the Arduino projects from the Visual Studio build process. 


note: If arduino is not the Startup Project the visual micro build commands will still build and upload but debugger function keys and short cuts such as "Continue" won't work