Hi @Joshua Thomas,
Welcome to Microsoft Q&A!
Do you mean that you can’t debug the project? What is your project type?
Please right-click on project node in the Solution Explorer > Set as Startup Project.
If it doesn’t work, you can create a new project and debug it again.
Besides, please ensure that you open a project, not a file. You can open an existing project via File > Open > Project/Solution > select the .sln file.
Sincerely,
Anna
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