Had an interesting error the other day. While reviewing an interns test project, I noticed that on a fresh clone of his repo, his website errored out on startup. For our projects we typically have a project for the website, and another for the business classes. For some reason, Visual Studio was trying to run the business project as the website.

This is easily fixed right-clicking the web project and selecting set as startup project, but this setting is stored in the .suo file which is not checked in. So why does this work in our other projects?

Doing some googling, came across this stackoverflow answer. It turns out that Visual Studio looks at the order of the projects in the solution file. Somehow, my intern added the business project first - I don’t think anyone has done that before.

All you need to do is manually edit the .sln file in a text editor, and move the “startup” project to the top of t he Project / EndProject blocks

Microsoft Visual Studio Solution File, Format Version 12.00
# Visual Studio 14
VisualStudioVersion = 14.0.23107.0
MinimumVisualStudioVersion = 10.0.40219.1
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MySiteApp", "MySite.App\MySiteApp.csproj", "{F5C8B11C-FF25-45B6-8F25-B1C779D4A053}"
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MySiteBusiness", "MySite.Business\MySiteBusiness.csproj", "{E9561B89-36A0-43C2-B9BA-970843316D23}"

On a related note, it seems like Microsoft can’t pick a file format and stay with it. the .suo file is binary, .config files are xml, and the .sln file is basically just simple keys and values.