I know there are many question related to this already on SO but none of them has woked for me till now.
I have a winform application but when I am trying to debug i
Just to add more information to user3414693's post it's possible there is a problem in the solution file such as referencing a project that doesn't exist or has had its name changed.
Unloading and reloading the project will recreate this file with the correct information potentially solving the problem.